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Abstract Cushing's syndrome (CS) arises from an excess of endogenous or exogenous cortisol, with Cushing's disease specifically implicating a pituitary adenoma and exaggerated adrenocorticotropic hormone (ACTH) production. Typically, Cushing's disease presents with characteristic symptoms such as weight gain, central obesity, moon face, and buffalo hump. This case report presents an unusual manifestation of CS in a 48-year-old male with a history of hypertension, where severe hypokalemia was the primary presentation. Initial complaints included bilateral leg swelling, muscle weakness, occasional shortness of breath, and a general feeling of not feeling well. Subsequent investigations revealed hypokalemia, metabolic alkalosis, and an abnormal response to dexamethasone suppression, raising concerns about hypercortisolism. Further tests, including 24-hour urinary free cortisol and ACTH testing, confirmed significant elevations. Brain magnetic resonance imaging (MRI) identified a pituitary macroadenoma, necessitating neurosurgical intervention. This case underscores the rarity of CS presenting with severe hypokalemia, highlighting the diagnostic challenges and the crucial role of a collaborative approach in managing such intricate cases. Introduction Cushing's syndrome (CS), characterized by excessive cortisol production, is well-known for its diverse and often conspicuous clinical manifestations. Cushing's disease is a subset of CS resulting from a pituitary adenoma overproducing adrenocorticotropic hormone (ACTH), leading to heightened cortisol secretion. The classic presentation involves a spectrum of symptoms such as weight gain, central obesity, muscle weakness, and mood alterations [1]. Despite its classic presentation, CS can demonstrate diverse and atypical features, challenging conventional diagnostic paradigms. This case report sheds light on a rare manifestation of CS, where severe hypokalemia was the primary clinical indicator. Notably, instances of CS prominently manifesting through severe hypokalemia are scarce in the literature [1,2]. Through this exploration, we aim to provide valuable insights into the diagnostic intricacies of atypical CS presentations, underscore the significance of a comprehensive workup, and emphasize the collaborative approach essential for managing such uncommon hormonal disorders. Case Presentation A 48-year-old male with a history of hypertension presented to his primary care physician with complaints of bilateral leg swelling, occasional shortness of breath, dizziness, and a general feeling of malaise persisting for 10 days. The patient reported increased water intake and urinary frequency without dysuria. The patient was diagnosed with hypertension eight months ago. He experienced progressive muscle weakness over two months, hindering his ability to perform daily activities, including using the bathroom. The primary care physician initiated a blood workup that revealed severe hypokalemia with a potassium level of 1.3 mmol/L (reference range: 3.6 to 5.2 mmol/L), prompting referral to the hospital. Upon admission, the patient was hypertensive with a blood pressure of 180/103 mmHg, a heart rate of 71 beats/minute, a respiratory rate of 18 breaths/minute, and an oxygen saturation of 96% on room air. Physical examination revealed fine tremors, bilateral 2+ pitting edema in the lower extremities up to mid-shin, abdominal distension with normal bowel sounds, and bilateral reduced air entry in the bases of the lungs on auscultation. The blood work showed the following findings (Table 1). Parameter Result Reference Range Potassium (K) 1.8 mmol/L 3.5-5.0 mmol/L Sodium (Na) 144 mmol/L 135-145 mmol/L Magnesium (Mg) 1.3 mg/dL 1.7-2.2 mg/dL Hemoglobin (Hb) 15.5 g/dL 13.8-17.2 g/dL White blood cell count (WBC) 13,000 x 103/µL 4.5 to 11.0 × 109/L Platelets 131,000 x 109/L 150-450 x 109/L pH 7.57 7.35-7.45 Bicarbonate (HCO3) 46 mmol/L 22-26 mmol/L Lactic acid 4.2 mmol/L 0.5-2.0 mmol/L Table 1: Blood work findings In order to correct the electrolyte imbalances, the patient received intravenous (IV) magnesium and potassium replacement and was later transitioned to oral. The patient was also started on normal saline at 100 cc per hour. To further investigate the complaint of shortness of breath, the patient underwent a chest X-ray, which revealed bilateral multilobar pneumonia (Figure 1). He was subsequently treated with ceftriaxone (1 g IV daily) and clarithromycin (500 mg twice daily) for seven days. Figure 1: A chest X-ray revealing (arrows) bilateral multilobar pneumonia With persistent abdominal pain and lactic acidosis, a computed tomography (CT) scan abdomen and pelvis with contrast was conducted, revealing a psoas muscle hematoma. Subsequent magnetic resonance imaging (MRI) depicted an 8x8 cm hematoma involving the left psoas and iliacus muscles. The interventional radiologist performed drainage of the hematoma involving the left psoas and iliacus muscles (Figure 2). Figure 2: Magnetic resonance imaging (MRI) depicting an 8x8 cm hematoma (arrow) involving the left psoas and iliacus muscles In light of the concurrent presence of hypokalemia, hypertension, and metabolic alkalosis, there arose concerns about Conn's syndrome, prompting consultation with endocrinology. Their recommended workup for Conn's syndrome included assessments of the aldosterone-renin ratio and random cortisol levels. The results unveiled an aldosterone level below 60 pmol/L (reference range: 190 to 830 pmol/L in SI units) and a plasma renin level of 0.2 pmol/L (reference range: 0.7 to 3.3 mcg/L/hr in SI units). Notably, the aldosterone-renin ratio was low, conclusively ruling out Conn's syndrome. The random cortisol level was notably elevated at 1334 nmol/L (reference range: 140 to 690 nmol/L). Furthermore, a low-dose dexamethasone suppression test was undertaken due to the high cortisol levels. Following the administration of 1 mg of dexamethasone at 10 p.m., cortisol levels were measured at 9 p.m., 3 a.m., and 9 a.m. the following day. The results unveiled a persistently elevated cortisol level surpassing 1655 nmol/L, signaling an abnormal response to dexamethasone suppression and raising concerns about a hypercortisolism disorder, such as CS. In the intricate progression of this case, the investigation delved deeper with a 24-hour urinary free cortisol level, revealing a significant elevation at 521 mcg/day (reference range: 10 to 55 mcg/day). Subsequent testing of ACTH portrayed a markedly elevated level of 445 ng/L, distinctly exceeding the normal reference range of 7.2 to 63.3 ng/L. A high-dose 8 mg dexamethasone test was performed to ascertain the source of excess ACTH production. The baseline serum cortisol levels before the high-dose dexamethasone suppression test were 1404 nmol/L, which decreased to 612 nmol/L afterward, strongly suggesting the source of excess ACTH production to be in the pituitary gland. A CT scan of the adrenal glands ruled out adrenal mass, while an MRI of the brain uncovered a 1.3x1.3x3.2 cm pituitary macroadenoma (Figure 3), leading to compression of adjacent structures. Neurosurgery was consulted, and they recommended surgical removal of the macroadenoma due to the tumor size and potential complications. The patient was referred to a tertiary care hospital for pituitary adenoma removal. Figure 3: Magnetic resonance imaging (MRI) of the brain depicting a 1.3x1.3x3.2 cm pituitary macroadenoma (star) Discussion CS represents a complex endocrine disorder characterized by excessive cortisol production. While the classic presentation of CS includes weight gain, central obesity, and muscle weakness, our case highlights an uncommon initial manifestation: severe hypokalemia. This atypical presentation underscores the diverse clinical spectrum of CS and the challenges it poses in diagnosis and management [1,2]. While CS typically presents with the classic symptoms mentioned above, severe hypokalemia as the initial manifestation is exceedingly rare. Hypokalemia in CS often results from excess cortisol-mediated activation of mineralocorticoid receptors, leading to increased urinary potassium excretion and renal potassium wasting. Additionally, metabolic alkalosis secondary to cortisol excess further exacerbates hypokalemia [3,4]. Diagnosing a case of Cushing's disease typically commences with a thorough examination of the patient's medical history and a comprehensive physical assessment aimed at identifying characteristic manifestations such as central obesity, facial rounding, proximal muscle weakness, and increased susceptibility to bruising. Essential to confirming the diagnosis are laboratory examinations, which involve measuring cortisol levels through various tests, including 24-hour urinary free cortisol testing, late-night salivary cortisol testing, and dexamethasone suppression tests. Furthermore, assessing plasma ACTH levels aids in distinguishing between pituitary-dependent and non-pituitary causes of CS. Integral to the diagnostic process are imaging modalities such as MRI of the pituitary gland, which facilitate the visualization of adenomas and the determination of their size and precise location [1-4]. Treatment for Cushing's disease primarily entails surgical removal of the pituitary adenoma via transsphenoidal surgery, with the aim of excising the tumor and restoring normal pituitary function. In cases where surgical intervention is unsuitable or unsuccessful, pharmacological therapies employing medications such as cabergoline (a dopamine receptor agonist) or pasireotide (a somatostatin analogue) may be considered to suppress ACTH secretion and regulate cortisol levels. Additionally, radiation therapy, whether conventional or stereotactic radiosurgery, serves as a supplementary or alternative treatment approach to reduce tumor dimensions and mitigate ACTH production [5,6]. To assess the effectiveness of treatment, manage any problem, and assure long-term illness remission, diligent long-term follow-up and monitoring are essential. Collaborative multidisciplinary care involving specialists such as endocrinologists, neurosurgeons, and other healthcare professionals is pivotal in optimizing patient outcomes and enhancing overall quality of life [2,4]. The prognosis of CS largely depends on the underlying cause, stage of the disease, and efficacy of treatment. Early recognition and prompt intervention are essential for improving outcomes and minimizing long-term complications. Surgical resection of the adrenal or pituitary tumor can lead to remission of CS in the majority of cases. However, recurrence rates vary depending on factors such as tumor size, invasiveness, and completeness of resection [2,3]. Long-term follow-up with endocrinologists is crucial for monitoring disease recurrence, assessing hormonal function, and managing comorbidities associated with CS. Conclusions In conclusion, our case report highlights the rarity of severe hypokalemia as the initial presentation of CS. This unique presentation underscores the diverse clinical manifestations of CS and emphasizes the diagnostic challenges encountered in clinical practice. A multidisciplinary approach involving endocrinologists, neurosurgeons, and radiologists is essential for the timely diagnosis and management of CS. Early recognition, prompt intervention, and long-term follow-up are essential for optimizing outcomes and improving the quality of life for patients with this endocrine disorder. References Nieman LK, Biller BM, Findling JW, Newell-Price J, Savage MO, Stewart PM, Montori VM: The diagnosis of Cushing's syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008, 93:1526-40. 10.1210/jc.2008-0125 Newell-Price J, Bertagna X, Grossman AB, Nieman LK: Cushing's syndrome. Lancet. 2006, 367:1605-17. 10.1016/S0140-6736(06)68699-6 Torpy DJ, Mullen N, Ilias I, Nieman LK: Association of hypertension and hypokalemia with Cushing's syndrome caused by ectopic ACTH secretion: a series of 58 cases. Ann N Y Acad Sci. 2002, 970:134-44. 10.1111/j.1749-6632.2002.tb04419.x Elias C, Oliveira D, Silva MM, Lourenço P: Cushing's syndrome behind hypokalemia and severe infection: a case report. Cureus. 2022, 14:e32486. 10.7759/cureus.32486 Fleseriu M, Petersenn S: Medical therapy for Cushing's disease: adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers. Pituitary. 2015, 18:245-52. 10.1007/s11102-014-0627-0 Pivonello R, De Leo M, Cozzolino A, Colao A: The treatment of Cushing's disease. Endocr Rev. 2015, 36:385-486. 10.1210/er.2013-1048 From https://www.cureus.com/articles/243881-unveiling-the-uncommon-cushings-syndrome-cs-masquerading-as-severe-hypokalemia?score_article=true#!/

Authors Stasiak M , Witek P, Adamska-Fita E, Lewiński A Received 27 December 2023 Accepted for publication 20 March 2024 Published 8 April 2024 Volume 2024:16 Pages 35—42 DOI https://doi.org/10.2147/DHPS.S453105 Checked for plagiarism Yes Review by Single anonymous peer review Peer reviewer comments 2 Editor who approved publication: Dr Hemalkumar B Mehta Download Article [PDF] Magdalena Stasiak,1 Przemysław Witek,2 Emilia Adamska-Fita,1 Andrzej Lewiński1,3 1Department of Endocrinology and Metabolic Diseases, Polish Mother’s Memorial Hospital—Research Institute, Lodz, Poland; 2Department of Internal Medicine, Endocrinology and Diabetes, Medical University of Warsaw; Mazovian Brodnowski Hospital, Warszawa, Poland; 3Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Lodz, Poland Correspondence: Magdalena Stasiak, Department of Endocrinology and Metabolic Diseases, Polish Mother’s Memorial Hospital—Research Institute, 281/289 Rzgowska Street, Lodz, 93-338, Poland, Tel +48502049292, Fax +48422711140, Email mstasiak33@gmail.com Abstract: Cushing’s disease (CD) is the most common cause of endogenous hypercortisolism. Osilodrostat was demonstrated to be efficient in treating CD, and the mean average dose required for CD control was < 11 mg/day. Potential differences in osilodrostat treatment between cortisol-producing adenoma (CPA) and CD have not been reported. The aim of this study was to present two patients with CPA in whom significant differences in the response to therapy compared to CD were found. We demonstrated a case of inverse response of cortisol levels with adrenal tumor progression during the initial dose escalation (Case 1). Simultaneously, severe exaggeration of hypercortisolism symptoms and life-threatening hypokalemia occurred. A further rapid dose increase resulted in the first noticeable cortisol response at a dose of 20 mg/day, and a full response at a dose of 45 mg/day. We also present a case that was initially resistant to therapy (Case 2). The doses required to achieve the first response and the full response were the same as those for Case 1. Our study demonstrated that osilodrostat therapy in patients with CPA may require a different approach than that in CD, with higher doses, faster dose escalation, and a possible initial inverse response or lack of response. Keywords: osilodrostat, adrenal adenoma, hypercortisolism, ACTH-independent, adverse events, hypokalemia Introduction Chronic persistent hypercortisolism is a life-threatening condition that requires effective treatment. Untreated exposure to excessive cortisol secretion leads to severely increased morbidity and mortality due to cardiovascular diseases, thromboembolic events, sepsis, visceral obesity, impairment of glucose metabolism, and dyslipidaea, as well as musculoskeletal disorders, such as myopathy, osteoporosis, and skeletal fractures. Moreover, neuropsychiatric disorders, such as impairment of cognitive function, depression, or mania, as well as impairment of reproductive function can frequently occur.1,2 Cushing’s disease (CD) – a disorder caused by a pituitary adenoma secreting adrenocorticotropic hormone (ACTH) – is the most common cause of hypercortisolism. Cushing’s syndrome (CS) includes all other causes of cortisol excess, including ectopic ACTH production as well as direct cortisol overproduction by adrenal adenoma (cortisol-producing adenoma [CPA]) or adrenocortical carcinoma (ACC). Approximately 10% of hypercortisolism cases result from CPA. The first line therapy is a surgical resection of the tumor, which is the source of hormone excess. However, in many patients surgery is not fully efficient and other therapies are required to reduce cortisol levels. Additionally, due to severe cardiovascular complications and unstable DM, the surgical approach sometimes entails unacceptable risk and it is frequently postponed until cortisol levels are lowered. Pharmacotherapy with steroidogenesis inhibitors reduces cortisol levels and improves the symptoms of hypercortisolism.1,2 As CD is the most common cause of cortisol excess, most studies have focused on the efficacy and safety of novel steroidogenesis inhibitors, including patients with CD only.3–6 This is exactly the case with osilodrostat – a new potent inhibitor of 11β-hydroxylase.3–6 More data are available for metyrapone efficacy and safety in CSA,7 as the drug has been available much longer than osilodrostat. A study by Detomas et al, which reported results of comparison of efficacy of metyrapone and osilodrostat, included 4 patients with adrenal CS, among whom one CPA patient was treated with osilodrostat.8 Osilodrostat is approved in the United States to treat CD in patients in whom pituitary surgery was not curative or is contraindicated.9 In Poland, osilodrostat therapy is available for patients with all kinds of endogenous hypercortisolism not curative with other approaches, within a national program of emergency access to drug technologies.10 Reports on osilodrostat application in CPA are highly valuable as data on potential differences in the treatment regimens between CD and CPA are scarce. Here, we present two patients with CPA in whom the response and doses of osilodrostat were different from those reported in patients with CD. The main purpose of this study was to demonstrate that the efficacy of osilodrostat in CPA is high, although initial resistance to treatment or even deterioration of hypercortisolism can occur during the application of lower doses of the drug. Materials and Methods Study Design and Patients We retrospectively analyzed medical files of two consecutive patients with CPA treated with osilodrostat. The analysis included medical history, laboratory and imaging results as well as a detailed reports of adverse events. Laboratory and Imaging Procedures Serum cortisol and ACTH levels were measured by electrochemiluminescence immunoassay (ECLIA) using a Cobas e601 analyzer (Roche Diagnostics, Indianapolis, IN, USA). UFC excretion was measured by chemiluminescent microparticle immunoassay (CMIA) using an Abbott Architect ci4100 analyzer (Abbott, Abbott Park, IL, USA). Cross-reactivity with 11-deoxycortisol for this method is very low (2.1% according to the manufacturer’s data). Potassium levels were measured by ion-selective electrode potentiometry using a Beckman Coulter DxC 700 AU Chemistry Analyzer (Beckman Coulter, Brea, CA, USA). Computed tomography (CT) imaging was performed using a Philips Ingenuity Core 128 system (Philips, the Netherlands). Ethics Procedures Informed consent was obtained from all subjects involved in the study. Written informed consent was obtained from the patients for publication of this paper. The approval of Institutional Ethics Committee was obtained to publish the case details (approval code KB 33/2023). Presentation of the Cases Case 1 A 51-year-old female was referred to our department in November 2021 because of CPA, disqualified from surgery because of severe hypertension with a poor response to antihypertensive therapy and uncontrolled DM despite high doses of insulin. Additionally, the patient presented with hyperlipidemia and severe obesity (BMI=50.7 kg/m2), gastritis, depression, and osteoarthritis. On admission, she complained of a tendency to gain weight, fragile skin that bruised easily, difficulty with wound healing, susceptibility to infections, and insomnia. Physical examination revealed a moon face with plethora, a buffalo hump, central obesity with proximal muscle atrophy, and purple abdominal striae. The CPA diagnosis was initially made two years earlier, but the patient did not qualify for surgery due to a hypertensive crisis. Soon after this episode, the SARS-CoV-2 pandemic began, and the patient was afraid of visiting any medical center because her son had died of COVID-19. Therefore, she was referred to our center for life-threatening hypercortisolism two years later. At the time of admission, computed tomography (CT) imaging revealed a right adrenal tumor of 34x24x37mm, with a basal density of 21 HU and a contrast washout rate typical for adenomas (83%). The size and CT characteristics were identical as they were two years earlier. High serum cortisol levels, undetectable ACTH concentrations, and a lack of physiological diurnal rhythm of cortisol secretion were observed (Table 1). Urinary free cortisol (UFC) excretion was 310 µg/24 h, with an upper normal limit (UNL) of 176 µg/24 h. No cortisol suppression was achieved in high-dose dexamethasone suppression test (DST) (Table 1). Other adrenal-related hormonal parameters were within normal ranges, with values as follows: DHEA-S 42.68 µg/dl, aldosterone 3.24 ng/mL, and renin 59.14 µIU/mL. Table 1 Laboratory Results Before Osilodrostat Therapy – Case 1 Due to multiple severe systemic complications, including uncontrolled hypertension, decompensated DM, and cardiac insufficiency, treatment with osilodrostat was introduced for life-saving pre-surgical management. Osilodrostat was started at a dose of 1 mg twice daily and gradually increased to 6 mg per day with actually an inverse response of serum cortisol level. The late-night cortisol level increased from 16 µg/dl to 25 µg/dl. As the full effect of the osilodrostat dose can occur even after a few weeks, the patient was discharged from hospital and instructed to contact her attending doctor immediately if any health deterioration was noticed. In the case of improvement in the patient’s condition, the next hospitalization was planned 3 weeks later. After three weeks of no contact with the patient, she was readmitted to our department with life-threatening escalation of hypercortisolism, severe hypokalemia, and further deterioration of hypertension, DM, cardiac insufficiency, dyspnea, and significant edemas, including facial edema. Treatments of hypertension, cardiac insufficiency, and DM were intensified, as presented in Table 2. Despite active potassium supplementation, life-threatening hypokalemia of 2.1 mmol/l occurred. Previously observed depression was exaggerated with severe anxiety and fear of death. The dose of osilodrostat was increased to 8 mg/day, and after three days of treatment a further elevation of serum cortisol was found, with an increase in UFC up to 9 × UNL (1546.2 µg/24 h). Due to an entirely unexpected inverse cortisol response, CT imaging was performed and revealed progression of the adenoma size to 39 × 36 × 40 mm, with a slight increase in density up to 27 HU as compared to the previous CT scan performed a month earlier (Figure 1). Table 2 Changes in the Most Important Parameters During Osilodrostat Therapy – Case 1 Figure 1 Progression of the adrenal adenoma size during the initial doses of osilodrostat: (a) CT scan directly before osilodrostat therapy – solid nodule 34x24x37 mm, basal density 21 HU; (b) CT scan during treatment with 8 mg of osilodrostat daily – solid nodule 39x36x40 mm, basal density of 27 HU. Considering the extremely high risk associated with such a rapid cortisol increase and related complications, decision of fast osilodrostat dose escalation was made. The dose was increased by 5 mg every other day, up to 45 mg per day, and, finally, a gradual decrease in the cortisol level (Table 2) was achieved, with UFC normalization to 168 µg/24 h. During dose escalation, no deterioration in the adverse effects (AEs) of osilodrostat was observed. Conversely, hypokalemia gradually improved despite a simultaneous reduction in potassium supplementation (Table 2). Facial edema decreased and the level of anxiety improved significantly. The course of hypertension severity as well as a summary of the main parameters controlled during treatment and the medications used are presented in Table 2. As soon as the cortisol level normalized, the patient was referred for surgery and underwent right adrenalectomy without any complications. Histopathology results confirmed a benign adenoma of the right adrenal gland (encapsulated, well-circumscribed tumor consisting of lipid-rich cells with small and uniform nuclei, mostly with eosinophilic intracytoplasmic inclusions). After surgery, hydrocortisone replacement therapy was administered. A few days after surgery, blood pressure and glucose levels gradually decreased, and the patient required reduction of antihypertensive and antidiabetic medications. After 22 months of follow-up, the patient’s general condition is good with no signs of recurrence. Antidepressant treatment is no longer required in this patient. Body mass index was significantly reduced to 40 kg/m2. The antihypertensive medication was completely discontinued, and the glucose level is controlled only with metformin. The patient still requires hydrocortisone substitution at a dose of 30 mg/day. Case 2 A 39-year-old female was referred to our department in November 2022 with a diagnosis of CPA and unstable hypertension, for which surgery was contraindicated. The patient was unsuccessfully treated with triple antihypertensive therapy (telmisartan 40 mg/day, nebivolol 5 mg/day, and lercanidipine 20 mg/day). The patient reported weight gain, muscle weakness, acne, fragile skin that bruised easily, and secondary amenorrhea. Other comorbidities included gastritis, hypercholesterolemia, and osteoporosis. Physical examination revealed typical signs of Cushing’s syndrome, such as abnormal fat distribution, particularly in the abdomen and supraclavicular fossae, proximal muscle atrophy, moon face, and multiple hematomas. A lack of a serum cortisol diurnal rhythm with high late-night serum cortisol and undetectable ACTH levels was found (Table 3). The short DST revealed no cortisol suppression (Table 3), and the UFC result was 725 µg/24 h, which exceeded the UNL more than four times. The serum levels of renin, aldosterone, and 24-h urine fractionated metanephrines were within the normal ranges. Computed tomography imaging revealed a left adrenal gland tumor measuring 25 × 26 × 22 mm, with a basal density of 32 HU and a washout rate typical for adenoma (76%). Table 3 Laboratory Results Before Osilodrostat Therapy – Case 2 Osilodrostat therapy was administered for preoperative management. The initial daily dose was 2 mg/day, increased gradually by 2 mg every day with no serum cortisol response (late night cortisol levels 15.8–18.5 µg/dl) and no AEs of the drug (Table 4). After the daily dose of osilodrostat reached 10 mg, it was escalated by 5 mg every other day, initially with no serum cortisol reduction. The dose was increased to 45 mg daily (with the lowest detected late-night serum cortisol of 9.6 µg/dl) (Table 4). Table 4 Changes in the Most Important Parameters During Osilodrostat Therapy – Case 2 After a week of administration of 45 mg daily, UFC normalization was achieved. Despite rapid dose escalation, no AEs were observed during the entire therapy period. Potassium levels were normal without any supplementation (the lowest detected serum potassium level was 3.9 mmol/l; all other results were over 4.0 mmol/l) (Table 4). After UFC normalization, left adrenalectomy was performed without complications. Histopathological examination revealed benign adrenal adenoma. Antihypertensive therapy was reduced only to 2.5 mg of nebivolol daily. The patient’s general condition improved significantly. Currently, hydrocortisone replacement therapy is administered at a dose of 15 mg/day. Discussion Osilodrostat is a novel potent steroidogenesis inhibitor whose efficacy and safety have been thoroughly analyzed in clinical trials of patients with CD, the most common cause of endogenous hypercortisolism. No clinical trial of osilodrostat therapy in CPA has been performed, as this disease constitutes only 10% of all cases of endogenous hypercortisolism. Moreover, osilodrostat is not approved by the FDA for hypercortisolism conditions other than CD.9 Therefore, data on potential differences in the treatment regimen are lacking. During the course of already reported trials in CD, osilodrostat doses were escalated slowly, every 2–3 weeks,3,5,6 with an excellent response to quite low doses of the drug.3–6 In the LINC 2 extension study the median average dose was 10.6 mg/day,5 while in the LINC 3 extension study and the LINC 4 study it was 7.4 mg/day and 6.9 mg/day, respectively.4,6 In most cases, a significant decrease of hypercortisolism was reported with the low doses of osilodrostat (4 or 10 mg/day). Moreover, some patients received 1 mg/day or even 1 mg every other day, with a good response.6 Even in rare cases of CD in whom initial short-term etomidate therapy was given at the beginning of osilodrostat therapy, due to highly severe life-threatening symptoms of hypercortisolism, the final effective dose of osilodrostat was much lower than that in our patients with CPA (25 mg/day vs 45 mg/day) and no increase of cortisol level was observed.11 It should be underlined that many cases of adrenal insufficiency during osilodrostat therapy in patients with CD have been reported,3–6,12,13 and – therefore – low initial dose with slow gradual dose escalation is recommended in patients with CD.1,6,13 In the cases presented here, CPA led to severe hypercortisolism, the complications of which constituted contraindications for surgery. Therefore, osilodrostat therapy was introduced as a presurgical treatment. In Case 1, the therapy was started at low doses according to the approved product characteristics.14 Due to the severity of hypertension, which was uncontrolled despite of active antihypertensive therapy, as well as to unstable DM, the doses were increased faster than recommended. Surprisingly, we immediately observed a gradual increase in hypercortisolism, in both serum cortisol levels and the UFC, with simultaneous burst of complications related to both hypercortisolism itself and 11β-hydroxylase inhibition. Life-threatening episodes of hypertensive crisis responded poorly to standard therapies. Severe exaggeration of cardiac insufficiency could probably be related to these episodes as well as to deep hypokalemia, which occurred despite potassium supplementation. Hypokalemia is a typical complication of treatment with 11β-hydroxylase inhibitors due to the accumulation of adrenal hormone precursors. However, Patient 1 required much higher doses of potassium supplementation, both parenteral and oral, than ever described during osilodrostat therapy.3–6,13 The dose of 20 mg/day of osilodrostat was the first one which led to noticeable cortisol reduction and a decrease in systolic blood pressure (SBP) to below 170 mmHg. Surprisingly, instead of the expected deterioration of hypokalemia, parenteral potassium administration could be stopped with an osilodrostat dose of 20 mg/day and oral supplementation was gradually reduced simultaneously with osilodrostat dose escalation. The reason why such severe hypokalemia occurred with low doses of osilodrostat and did not deteriorate further seems complex. One possible reason is the administration of high doses of potassium-saving antihypertensive drugs such as spironolactone and the angiotensin II receptor antagonist telmisartan. Additionally, one can consider other possible mechanisms, such as downregulation of the receptors of deoxycorticosterone (DOC) or other adrenal hormone precursors. However, this hypothesis requires further research and confirmation. Such an improvement of the potassium level during osilodrostat dose escalation was previously demonstrated in a patient with CD.11 Interestingly, in our Patient 2, no potassium supplementation was required during the whole time of osilodrostat therapy, although the doses were increased intensively up to the finally effective dose, which was the same (45 mg/day) as for Patient 1. In Patient 2, no actual response to doses lower than 20 mg/day was observed. UFC normalization was achieved after a week of administration of 45 mg/day, five weeks from the beginning of therapy. Although UFC normalization is not always required in pre-surgical treatment, clinical symptoms significantly improved in our patients only after the UFC upper normal level was achieved. The present paper is one of only a few reports focused on osilodrostat therapy in CPA, and the only one presenting a different therapy course as compared to patients with CD. No case of CPA resistance to low doses of osilodrostat has been described. It should be underlined that in our report “low doses” of osilodrostat were higher than the average mean doses of osilodrostat used in clinical trials in patients with CD.3–6 Therefore, they should not generally be considered low but only much lower than those which were effective in our patients. Malik and Ben-Shlomo presented a case of CPA treated with osilodrostat, with an immediate decrease in cortisol level at 4 mg/day and adrenal insufficiency symptoms after dose escalation to 8 mg/day.15 Similar to our two cases, their patient was a middle-aged female with normal results of all other adrenal parameters, such as renin, angiotensin, or metanephrine levels. However, a CT scan was not performed (or presented), while magnetic resonance imaging revealed an indeterminate adrenal gland mass without a typical contrast phase/out-of-phase dropout for adenoma.15 Therefore, different morphology of cortisol-secreting adrenal tumor can potentially be considered a reason of the different response to treatment. Tanaka et al performed a multicenter study on the efficacy and safety of osilodrostat in Japanese patients with non-CD Cushing’s syndrome.16 Five patients with CPA were included in the study, and none of them required osilodrostat doses higher than 10 mg/day to achieve UFC normalization. However, most of the patients presented by Tanaka et al were previously treated with metyrapone,16 whereas both of our patients were treatment-naive. Previous metyrapone therapy may be considered as a potential reason of better response to osilodrostat. This hypothesis was confirmed in the quoted study by Tanaka et al, who demonstrated that at week 12 the median percent changes in the mUFC values were higher in patients previously treated with metyrapone (–98.97%) than in treatment-naive cases (–86.65%).16 Detomas et al performed a comparison of efficacy and safety of osilodrostat and metyrapone, with one CPA patients included in a group treated with osilodrostat, however no data on a dose required for a disease control are available separately for this particular patient.8 To the best of our knowledge, no more CPA cases have been described and therefore no further comparison is available. Higher doses of osilodrostat were administered to a group of seven patients with hypercortisolism due to adrenocortical carcinoma (ACC) presented by Tabarin et al.17 A full control of hypercortisolism was achieved in one patient for each dose of 4, 8, 10, and 20 mg/day, and in three patients treated with 40 mg/day.17 These patients, however received other therapies including mitotane and chemotherapy, which can significantly modify the response to osilodrostat. Several authors have reported the phenomenon of a partial or total loss of response to osilodrostat.5,16,17 In such cases, a response to treatment was initially achieved and then lost during treatment with the same dose. A further increase in osilodrostat dose usually resulted in the response resumption.5,16,17 Such a situation could not be suspected in either of our cases. The presented cases provide a novel insight into modalities of treatment with osilodrostat in patients with CPA and demonstrate for the first time that an inverse cortisol response is possible in CPA cases, especially those with a higher CT density of adrenal adenoma. Such a situation should not be considered a contraindication to dose escalation. Conversely, the dose should be increased more intensively so as to achieve the initial efficacy threshold, which was 20 mg/day in both of our patients. The fully efficient dose that allowed UFC normalization was more than twice as high (45 mg/day in both cases). A similar approach should be applied in patients who do not respond to lower doses, such as Patient 2. The safety of osilodrostat therapy is strictly individual and not dose dependent in patients with CPA. Adverse events, including hypokalemia, severe hypertension, and edema, can be of life-threatening severity or may not occur regardless of the dose. Moreover, AEs of high severity may decrease with osilodrostat dose escalation. Our study demonstrated that osilodrostat is efficient and can be used in patients with CPA as a pre-surgical therapy if surgery is contraindicated due to hypercortisolism complications. Our study presented two cases of CPA treated with osilodrostat, and a small size of our group is the main limitation of this report. Future research is required to confirm our observations. Conclusion In some patients with CPA, the doses of osilodrostat required for disease control can be much higher than those previously reported. Acceleration of the dose increase can be fast, and the risk of overdosing, adrenal insufficiency, and later necessity of dose reduction seem to be much lower than it could be expected. Low initial doses (<20 mg/day in our study) can be entirely ineffective or can even cause exacerbation of hypercortisolism, whereas high doses (45 mg/day in the present study) are efficient in pre-surgery UFC normalization. AEs associated with osilodrostat can be rapid, with severe hypokalemia despite active potassium supplementation, or may not occur even if high doses of osilodrostat are applied. Therefore, close monitoring for potential AEs is necessary. Acknowledgments The abstract included some parts of this paper was presented at the European Congress of Endocrinology ECE2023 as a rapid communication. The abstract was published in the Endocrine Abstracts Vol. 90 [https://www.endocrine-abstracts.org/ea/0090/]. Funding The publication of this report was financially supported by the statutory funds of the Polish Mother’s Memorial Hospital – Research Institute, Lodz, Poland. Disclosure Professor Przemysław Witek reports personal fees from Investigator in the clinical trials paid by Novartis and Recordati Rare Diseases, outside the submitted work; lectures fees from Recordati Rare Diseases, Strongbridge, IPSEN. The authors report no other conflicts of interest in this work. References 1. Fleseriu M, Auchus R, Bancos I, et al. Consensus on diagnosis and management of Cushing’s disease: a guideline update. Lancet Diabetes Endocrinol. 2021;9(12):847–875. doi:10.1016/S2213-8587(21)00235-7 2. Pivonello R, Isidori AM, De Martino MC, et al. Complications of Cushing’s syndrome: state of the art. Lancet Diabetes Endocrinol. 2016;4(7):611–629. doi:10.1016/S2213-8587(16)00086-3 3. Pivonello R, Fleseriu M, Newell-Price J, et al. Efficacy and safety of osilodrostat in patients with Cushing’s disease (LINC 3): a multicentre Phase III study with a double-blind, randomised withdrawal phase. Lancet Diabetes Endocrinol. 2020;8(9):48–761. doi:10.1016/S2213-8587(20)30240-0 4. Fleseriu M, Newell-Price J, Pivonello R, et al. Long-term outcomes of osilodrostat in Cushing’s disease: LINC 3 study extension. Eur J Endocrinol. 2022;187(4):531–541. doi:10.1530/EJE-22-0317 5. Fleseriu M, Biller BMK, Bertherat J, et al. Long-term efficacy and safety of osilodrostat in Cushing’s disease: final results from a Phase II study with an optional extension phase (LINC 2). Pituitary. 2022;25(6):959–970. doi:10.1007/s11102-022-01280-6 6. Gadelha M, Bex M, Feelders RA, et al. Randomized trial of osilodrostat for the treatment of Cushing disease. J Clin Endocrinol Metab. 2022;107(7):e2882–e2895. doi:10.1210/clinem/dgac178 7. Daniel E, Aylwin S, Mustafa O, et al. Effectiveness of metyrapone in treating cushing’s syndrome: a retrospective multicenter study in 195 patients. J Clin Endocrinol Metab. 2015;100(11):4146–4154. doi:10.1210/jc.2015-2616 8. Detomas M, Altieri B, Deutschbein T, et al. Metyrapone versus osilodrostat in the short-term therapy of endogenous cushing’s syndrome: results from a single center cohort study. Front Endocrinol. 2022;13:903545. doi:10.3389/fendo.2022.903545 9. U.S. food and drug administration home page. Available from: https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-adults-cushings-disease. Accessed March 22, 2023. 10. Agency for health technology assessment and tariff system home page. Available from: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwj6ypGbsfT9AhUMzYsKHTgAD2EQFnoECA8QAQ&url=https%3A%2F%2Fbipold.aotm.gov.pl%2Fassets%2Ffiles%2Fwykaz_tli%2FRAPORTY%2F2020_010.pdf&usg=AOvVaw3P2Q85gwi3JcxKkW3uxfOb. Accessed March 22, 2022. 11. Dzialach L, Sobolewska J, Respondek W, et al. Cushing’s syndrome: a combined treatment with etomidate and osilodrostat in severe life-threatening hypercortisolemia. Hormones. 2022;21(4):735–742. doi:10.1007/s42000-022-00397-4 12. Ekladios C, Khoury J, Mehr S, et al. Osilodrostat-induced adrenal insufficiency in a patient with Cushing’s disease. Clin Case Rep. 2022;10(11):e6607. doi:10.1002/ccr3.6607 13. Fleseriu M, Biller BMK. Treatment of Cushing’s syndrome with osilodrostat: practical applications of recent studies with case examples. Pituitary. 2022;25(6):795–809. doi:10.1007/s11102-022-01268-2 14. Summary of product characteristics. Available from: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwim1_KdsvT9AhVq-ioKHUZKAc4QFnoECA4QAQ&url=https%3A%2F%2Fwww.ema.europa.eu%2Fen%2Fdocuments%2Fproduct-information%2Fisturisa-epar-product-information_pl.pdf&usg=AOvVaw0S8nayCTdqNh1LsEcXVLEu. Accessed March 24, 2023. 15. Malik RB, Ben-Shlomo A. Adrenal cushing’s syndrome treated with preoperative osilodrostat and adrenalectomy. AACE Clin Case Rep. 2022;8(6):267–270. doi:10.1016/j.aace.2022.10.001 16. Tanaka T, Satoh F, Ujihara M, et al. A multicenter, Phase 2 study to evaluate the efficacy and safety of osilodrostat, a new 11β-hydroxylase inhibitor, in Japanese patients with endogenous Cushing’s syndrome other than Cushing’s disease. Endocr J. 2020;67(8):841–852. doi:10.1507/endocrj.EJ19-0617 17. Tabarin A, Haissaguerre M, Lassole H, et al. Efficacy and tolerance of osilodrostat in patients with Cushing’s syndrome due to adrenocortical carcinomas. Eur J Endocrinol. 2022;186(2):K1–K4. doi:10.1530/EJE-21-1008 © 2024 The Author(s). This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. 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Abstract Here, we present the case of a 40-year-old man in whom the diagnosis of ectopic adrenocorticotropin (ACTH) syndrome went unrecognized despite evaluation by multiple providers until it was ultimately suspected by a nephrologist evaluating the patient for edema and weight gain. On urgent referral to endocrinology, screening for hypercortisolism was positive by both low-dose overnight dexamethasone suppression testing and 24-hour urinary free cortisol measurement. Plasma ACTH values confirmed ACTH-dependent Cushing syndrome. High-dose dexamethasone suppression testing was suggestive of ectopic ACTH syndrome. Inferior petrosal sinus sampling demonstrated no central-to-peripheral gradient, and 68Ga-DOTATATE scanning revealed an avid 1.2-cm left lung lesion. The suspected source of ectopic ACTH was resected and confirmed by histopathology, resulting in surgical cure. While many patients with Cushing syndrome have a delayed diagnosis, this case highlights the critical need to increase awareness of the signs and symptoms of hypercortisolism and to improve the understanding of appropriate screening tests among nonendocrine providers. ACTH-dependent Cushing syndrome, ectopic ACTH, ectopic Cushing syndrome, glucocorticoid excess Issue Section: Case Report Introduction Even in the face of overt clinical signs and symptoms of hypercortisolism, diagnosing Cushing syndrome requires a high index of suspicion, and people with hypercortisolism experience a long road to diagnosis. In a recent meta-analysis including more than 5000 patients with Cushing syndrome, the mean time to diagnosis in all Cushing syndrome, including Cushing disease and ectopic adrenocorticotropin (ACTH) syndrome, was 34 months (1). Reasons for delayed diagnosis are multifactorial, including the nonspecific nature of subjective symptoms and objective clinical signs, as well as notorious challenges in the interpretation of diagnostic testing. Furthermore, the health care system's increasingly organ-specific referral patterns obfuscate multisystem disorders. Improving the recognition of and decreasing time to diagnosis in Cushing syndrome are critical factors in reducing morbidity and mortality. Here, we present the case of a patient who, despite classic signs of Cushing syndrome as well as progressive physical and mental decline, remained undiagnosed for more than 3 years while undergoing repeated evaluation by primary care and subspecialty providers. The case (1) highlights the lack of awareness of Cushing syndrome as a potential unifying diagnosis for multiorgan system problems; (2) underscores the necessity of continued education on the signs and symptoms of hypercortisolism, appropriate screening for hypercortisolism, and early referral to endocrinology; and (3) provides an opportunity for systemic change in clinical laboratory practice that could help improve recognition of pathologic hypercortisolism. Case Presentation In August 2018, a previously healthy 40-year-old man with ongoing tobacco use established care with a primary care provider complaining that he had been ill since the birth of his son 13 months prior. He described insomnia, headaches, submandibular swelling, soreness in his axillary and inguinal regions, and right-sided chest discomfort (Fig. 1). Previously, he had been diagnosed with sinusitis, tonsillitis, and allergies, which had been treated with a combination of antibiotics, antihistamines, and intranasal glucocorticoids. He was referred to otolaryngology where, in the absence of cervical lymphadenopathy, he was diagnosed with sternocleidomastoid pain with recommendations to manage conservatively with stretching and massage. A chest x-ray demonstrated a left apical lung nodule. Symptoms continued unabated throughout 2019, now with a cough. Repeat chest x-ray demonstrated opacities lateral to the left hilum that were attributed to vascular structures. Figure 1. Open in new tabDownload slide Timeline of development of subjective symptoms and objective clinical findings preceding diagnosis and surgical cure of ectopic Cushing syndrome. In May 2020, increasingly frustrated with escalating symptoms, the patient transitioned care to a second primary care provider and was diagnosed with hypertension. He complained of chronic daily headaches that prompted brain imaging with magnetic resonance imaging (MRI), which noted findings consistent with left maxillary silent sinus syndrome. He was sent back to otolaryngology, which elected to proceed with sinus surgery. During this time, he suffered a fibular fracture for which he was evaluated by orthopedic surgery. In the second half of 2020, he was seen by neurology to evaluate his chronic headaches and paresthesias with electromyography demonstrating a left ulnar mononeuropathy consistent with cubital tunnel syndrome. His primary care provider diagnosed him with fibromyalgia for which he started physical therapy, and he was referred to a pain clinic for cognitive behavioral therapy. Unfortunately his wife, dealing with her husband's increasing cognitive and personality changes including irritability and aggression, filed for divorce. At the end of 2020, the patient developed bilateral lower extremity edema and was prescribed hydrochlorothiazide, subsequently developing hypokalemia attributed to diuretic use. With worsening bilateral lower extremity edema and new dyspnea on exertion, he was evaluated for heart failure with an echocardiogram, which was unremarkable. Over the next several months, he gained approximately 35 pounds (∼16 kg). It was in the setting of weight gain that he was first evaluated for hypercortisolism with random serum cortisol of 22.8 mcg/dL (629 nmol/L) and 45.6 mcg/dL (1258 nmol/L) in the late morning and mid-day, respectively. No reference range was provided for the times of day at which these laboratory values were drawn. Although these serum cortisol values were above provided reference ranges for other times of day, they were not flagged as abnormal by in-house laboratory convention, and they were overlooked. The search for other etiologies of his symptoms continued. In early 2021, diuretic therapy and potassium supplementation were escalated for anasarca. He developed lower extremity cellulitis and received multiple courses of antibiotics. Skin biopsy performed by dermatology demonstrated disseminated Mycobacterium and later Serratia (2), prompting referral to infectious disease for management. Additional subspecialty referrals included rheumatology (polyarthralgia) and gastroenterology (mildly elevated alanine transaminase with planned liver biopsy). In July 2021, he was evaluated for edema by nephrology, where the constellation of subjective symptoms and objective data including hypertension, central weight gain, abdominal striae, fracture, edema, easy bruising, medication-induced hypokalemia, atypical infections, and high afternoon serum cortisol were noted, and the diagnosis of Cushing syndrome was strongly suspected. Emergent referral to endocrinology was placed. Diagnostic Assessment At his first clinic visit with endocrinology in June 2021, the patient’s blood pressure was well-controlled on benazepril. Following weight gain of 61 pounds (∼28 kg) in the preceding 2 years, body mass index was 33. Physical examination demonstrated an ill-appearing gentleman with dramatic changes when compared to prior pictures (Fig. 2), including moon facies, dorsocervical fat pad, violaceous abdominal striae, weeping lower extremity skin infections, an inability to stand without assistance from upper extremities, and depressed mood with tangential thought processes. Figure 2. Open in new tabDownload slide Photographic representation of physical changes during the years leading up to diagnosis of ectopic Cushing syndrome in June 2021 and after surgical resection of culprit lesion. Diagnostic workup for hypercortisolism included a morning cortisol of 33.4 mcg/dL (922 nmol/L) (normal reference range, 4.5-22.7 mcg/dL) and ACTH of 156 pg/mL (34 pmol/L) (normal reference range, 7.2-63 pg/mL) following bedtime administration of 1-mg dexamethasone, and 24-hour urine free cortisol of 267 mcg/24 hours (737 nmol/24 hours) (normal reference range, 3.5-45 mcg/24 hours). Morning serum cortisol and plasma ACTH following bedtime administration of 8-mg dexamethasone were 27.9 mcg/dL (770 nmol/L) and 98 pg/mL (22 pmol/L), respectively. Given concern for potential decompensation, he was hospitalized for expedited work-up. Brain MRI did not demonstrate a pituitary lesion (Fig. 3), and inferior petrosal sinus sampling under desmopressin stimulation showed no central-to-peripheral gradient (Table 1). He underwent a positron emission tomography–computed tomography 68Ga-DOTATATE scan that demonstrated a 1.2-cm left pulmonary nodule with radiotracer uptake (Fig. 4). Figure 3. Open in new tabDownload slide A, Precontrast and B, postcontrast T1-weighted sagittal magnetic resonance imaging of the sella. Images were affected by significant motion degradation, precluding clear visualization of the pituitary gland on coronal imaging. Figure 4. Open in new tabDownload slide 68Ga-DOTATATE imaging. A, Coronal and B, axial views of the chest after administration of radiopharmaceutical. Arrow in both panels indicates DOTATATE-avid 1.2-cm left lung lesion. Table 1. Bilateral petrosal sinus and peripheral adrenocorticotropin levels preintravenous and postintravenous injection of desmopressin acetate 10 mcg Time post DDAVP, min Left petrosal ACTH Left petrosal:peripheral ACTH Right petrosal ACTH Right petrosal:peripheral ACTH Peripheral ACTH Left:right petrosal ACTH 0 172 pg/mL (37.9 pmol/L) 1.1 173 pg/mL (38.1 pmol/L) 1.2 150 pg/mL (33.0 pmol/L) 1.0 3 288 pg/mL (63.4 pmol/L) 1.8 292 pg/mL (64.3 pmol/L) 1.8 162 pg/mL (35.7 pmol/L) 1.0 5 348 pg/mL (76.6 pmol/L) 1.8 341 pg/mL (75.1 pmol/L) 1.8 191 pg/mL (42.1 pmol/L) 1.0 10 367 pg/mL (80.8 pmol/L) 1.3 375 pg/mL (82.6 pmol/L) 1.3 278 pg/mL (61.2 pmol/L) 1.0 Abbreviations: ACTH, adrenocorticotropin; DDAVP, desmopressin acetate. Open in new tab Treatment The patient was started on ketoconazole 200 mg daily for medical management of ectopic ACTH-induced hypercortisolism while awaiting definitive surgical treatment. Within a month of initial endocrinology evaluation, he underwent thoracoscopic left upper lobe wedge resection with intraoperative frozen histopathology section consistent with a well-differentiated neuroendocrine tumor and final pathology consistent with a well-differentiated neuroendocrine tumor. Staining for ACTH was positive (Fig. 5). Postoperative day 1 morning cortisol was 1.4 mcg/dL (39 nmol/L) (normal reference range, 4.5-22.7 mcg/dL). He was started on glucocorticoid replacement with hydrocortisone and was discharged from his surgical admission on hydrocortisone 40 mg in the morning and 20 mg in the afternoon. Figure 5. Open in new tabDownload slide Lung tumor histopathology. A, The tumor was epicentered around a large airway (asterisk) and showed usual architecture for carcinoid tumor. B, The tumor cells had monomorphic nuclei with a neuroendocrine chromatin pattern, variably granulated cytoplasm, and a delicate background vascular network. By immunohistochemistry, the tumor cells were strongly positive for C, synaptophysin; D, CAM5.2; and E, adrenocorticotropin. F, Ki-67 proliferative index was extremely low (<1%). Outcome and Follow-up Approximately 12 days after discharge, the patient was briefly readmitted from the skilled nursing facility where he was receiving rehabilitation due to a syncopal event attributed to hypovolemia. This was felt to be secondary to poor oral intake in the setting of both antihypertensive and diuretic medications as well as an episode of emesis earlier in the morning precluding absorption of his morning hydrocortisone dose. Shortly after this overnight admission, he was discharged from his skilled nursing facility to home. In the first month after surgery, he lost approximately 30 pounds (∼14 kg) and had improvements in sleep and mood. Eight months after surgery, hydrocortisone was weaned to 10 mg daily. Cosyntropin stimulation testing holding the morning dose showed 1 hour cortisol 21.5 mcg/dL (593 nmol/L). Hydrocortisone was subsequently discontinued. In June 2022, 1 year following surgery, 3 sequential midnight salivary cortisol tests were undetectable. At his last visit with endocrinology in June 2023, he felt well apart from ongoing neuropathic pain in his feet and continued but improved mood disturbance. Though his health has improved dramatically, he continues to attribute his divorce and substantial life disruption to his undiagnosed hypercortisolism. Discussion Endogenous neoplastic hypercortisolism encompasses a clinical spectrum from subclinical disease, as is common in benign adrenal cortical adenomas, to overt Cushing syndrome of adrenal, pituitary, and ectopic origin presenting with dramatic clinical manifestations (3) and long-term implications for morbidity and mortality (4). Even in severe cases, a substantial delay in diagnosis is common. In this case, despite marked hypercortisolism secondary to ectopic ACTH syndrome, the patient's time from first symptoms to diagnosis was more than 3 years, far in excess of the typical time to diagnosis in this subtype, noted to be 14 months in 1 study (1). He initially described a constellation of somatic symptoms including subjective neck swelling, axillary and inguinal soreness, chest discomfort, and paresthesias, and during the year preceding diagnosis, he developed hypertension, fibular fracture, mood changes, weight gain, peripheral edema, hypokalemia, unusual infections, and abdominal striae. Each of these symptoms in isolation is a common presentation in the primary care setting, therefore the challenge arises in distinguishing common, singular causes from rare, unifying etiologies, especially given the present epidemics of diabetes, obesity, and associated cardiometabolic abnormalities. By Endocrine Society guidelines, the best discriminatory features of Cushing syndrome in the adult population are facial plethora, proximal muscle weakness, abdominal striae, and easy bruising (5). Furthermore, Endocrine Society guidelines suggest evaluating for Cushing disease when consistent clinical features are present at a younger-than-expected age or when these features accumulate and progress, as was the case with our patient (5). However, even when the diagnosis is considered, the complexities of the hypothalamic-pituitary-adrenal axis make selection and interpretation of screening tests challenging outside the endocrinology clinic. We suspect that in most such situations, a random serum cortisol measurement is far more likely to be ordered than a validated screening test, such as dexamethasone suppression testing, urine free cortisol, and late-night salivary cortisol per Endocrine Society guidelines (5). Although random serum cortisol values are not considered a screening test for Cushing syndrome, elevated values can provide a clue to the diagnosis in the right clinical setting. In this case, 2 mid-day serum cortisols were, by in-house laboratory convention, not flagged as abnormal despite the fact that they were above the upper limit of provided reference ranges. We suspect that the lack of electronic medical record flagging of serum cortisol values contributed to these values being incorrectly interpreted as ruling out the diagnosis. Cushing syndrome remains among the most evasive and difficult diagnoses in medicine due to the doubly difficult task of considering the disorder in the face of often protean signs and symptoms and subsequently conducting and interpreting screening tests. The challenges this presents for the nonendocrinologist have recently been recognized by a group in the United Kingdom after a similarly overlooked case (6). We believe that our case serves as a vivid illustration of the diagnostic hurdles the clinician faces and as a cautionary tale with regard to the potential downstream effects of a delay in diagnosis. Standardization of clinical laboratory practices in flagging abnormal cortisol values is one such intervention that may aid the busy clinician in more efficiently recognizing laboratory results suggestive of this diagnosis. While false-positive case detection is a significant downside to this approach, given the potential harm in delayed or missed diagnosis, the potential benefits may outweigh the risks. Learning Points People with Cushing syndrome frequently experience a prolonged time to diagnosis, in part due to lack of recognition in the primary care and nonendocrine subspecialty settings of the constellation of clinical findings consistent with hypercortisolism. Endocrine Society guidelines recommend against random serum cortisol as initial testing for Cushing syndrome in favor of dexamethasone suppression testing, urine free cortisol, and late-night salivary cortisol. Increased awareness of Cushing syndrome by primary care providers and specialists in other fields could be an important and impactful mechanism to shorten the duration of symptom duration in the absence of diagnosis and hasten cure where cure is achievable. We suggest clinical laboratories consider standardizing flagging abnormal cortisol values to draw attention to ordering providers and perhaps lower the threshold for endocrinology referral if there is any uncertainty in interpretation, especially in the context of patients with persistent symptoms and elusive diagnoses. Acknowledgments We are grateful to the patient for allowing us to present his difficult case to the community with the hopes of improving time to diagnosis for patients with hypercortisolism. Contributors All authors made individual contributions to authorship. J.M.E., E.M.Z., and K.R.K. were involved in the diagnosis and management of this patient. B.C.M., J.M.E., E.M.Z., and K.R.K. were involved in manuscript submission. S.M.J. performed and analyzed histopathology and prepared the figure for submission. All authors reviewed and approved the final draft. Funding No public or commercial funding. Disclosures J.M.E. was on the editorial board of JCEM Case Reports at the time of initial submission. Informed Patient Consent for Publication Signed informed consent obtained directly from the patient. Data Availability Statement Data sharing is not applicable to this article as no data sets were generated or analyzed during the current study. References 1 Rubinstein G , Osswald A , Hoster E , et al. Time to diagnosis in Cushing's syndrome: a meta-analysis based on 5367 patients . J Clin Endocrinol Metab . 2020 ; 105 ( 3 😞 dgz136 . Google Scholar Crossref PubMed WorldCat 2 Park MA , Gaghan LJ , Googe PB , Klein KR , Mervak JE . Disseminated cutaneous Mycobacterium chelonae infection as a presenting sign of ectopic adrenocorticotropic hormone syndrome . JAAD Case Rep . 2021 ; 18 : 79 ‐ 81 . Google Scholar Crossref PubMed WorldCat 3 Reincke M , Fleseriu M . Cushing syndrome: a review . JAMA . 2023 ; 330 ( 2 😞 170 ‐ 181 . Google Scholar Crossref PubMed WorldCat 4 Puglisi S , Perini AME , Botto C , Oliva F , Terzolo M . Long-term consequences of Cushing's syndrome: a systematic literature review . J Clin Endocrinol Metab . 2024; 109 ( 3 😞 e901 ‐ e909 . Crossref PubMed WorldCat 5 Nieman LK , Biller BMK , Findling JW , et al. The diagnosis of Cushing's syndrome: an Endocrine Society clinical practice guideline . J Clin Endocrinol Metab . 2008 ; 93 ( 5 😞 1526 ‐ 1540 . Google Scholar Crossref PubMed WorldCat 6 Scoffings K , Morris D , Pullen A , Temple S , Trigell A , Gurnell M . Recognising and diagnosing Cushing's syndrome in primary care: challenging but not impossible . Br J Gen Pract . 2022 ; 72 ( 721 😞 399 ‐ 401 . Google Scholar Crossref PubMed WorldCat Abbreviations ACTH adrenocorticotropin MRI magnetic resonance imaging © The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com From https://academic.oup.com/jcemcr/article/2/3/luae034/7618559?login=false

Abstract Cushing’s syndrome is a constellation of features occurring due to high blood cortisol levels. We report a case of a 47-year-old male with a history of recurrent olfactory neuroblastoma (ONB). He presented with bilateral lower limb weakness and anosmia and was found to have Cushing’s syndrome due to high adrenocorticotropic hormone (ACTH) levels from an ectopic source, ONB in this case. Serum cortisol and ACTH levels declined after tumor removal. Introduction Olfactory neuroblastoma (ONB), or esthesioneuroblastoma, is a rare malignancy arising from neuroepithelium in the upper nasal cavity. It represents approximately 2% of all nasal passage tumors, with an incidence of approximately 0.4 per 2.5 million individuals [1]. ONB shares similar histological features with small round blue cell neoplasms of the nose. Ectopic hormone secretion is a very rare feature associated with these tumors. Five-year overall survival is reported to be between 60% and 80% [2,3]. The age distribution is either in the fifth to sixth decade of life [4,5], or in the second and sixth decades [6]. Features of Cushing’s syndrome (moon face, buffalo hump, central obesity hypertension, fragile skin, easy bruising, fatigue, muscle weakness) are due to high blood cortisol levels [7]. It can be either primary (cortisol-secreting adrenal tumor), secondary (adrenocorticotropic hormone (ACTH)-secreting pituitary tumor, also called Cushing disease), or ectopic ACTH secretion (from a non-pituitary source). All three types share similar features [8]. Ectopic ACTH syndrome (EAS) is due to an extra pituitary tumor, producing ACTH. It accounts for 12-17% of Cushing's syndrome cases [9]. Most cases of EAS-producing tumors are in the lungs, mediastinum, neuroendocrine tumors of the gastrointestinal tract, and pheochromocytomas [9]. Ectopic ACTH secretion from an ONB is very rare. As of 2015, only 18 cases were reported in the literature [10]. Here, we report such a case. Case Presentation Our patient is a 47-year-old Bangladeshi male, with a history of recurrent ONB that was resected twice in the past (transsphenoidal resection in 2016 and 2019) with adjuvant radiotherapy, no chemotherapy was given. He also had diabetes mellitus type 1 (poorly controlled) and hypertension. He presented with bilateral lower limb weakness, anosmia, decreased oral intake, loss of taste for one week, and bilateral submandibular swelling that increased in size gradually over the past two years. There was no history of fever, cough, abdominal pain, or exposure to sick contacts. The patient reported past episodes of similar symptoms, but details are unclear. The patient's family history is positive for diabetes mellitus type 1 in both parents. Lab tests in the emergency department showed hypokalemia and hyperglycemia as detailed in Table 1. He was admitted for further workup of the above complaints. Test Patient Results Reference Range Unit Status Hemoglobin 14.7 13-17 g/dL Normal White blood cell (WBC) 17.9 4-10 10*9/L High Neutrophils 15.89 2-7 10*9/L High Lymphocytes 1.07 1-3 10*9/L Normal Sodium 141 136-145 mmol/L Normal Potassium 2.49 3.5-5.1 mmol/L Low (Panic) Chloride 95 98-107 mmol/L Low Glucose 6.52 4.11-5.89 mmol/L Elevated C-reactive protein (CRP) 0.64 Less than 5 mg/L Normal Erythrocyte sedimentation rate (ESR) 2 0-30 mm/h Normal Creatinine 73 62-106 µmol/L Normal Uric acid 197 202.3-416.5 µmol/L Normal Alanine aminotransferase (ALT) 33.2 0-41 U/L Normal Aspartate aminotransferase (AST) 18.6 0-40 U/L Normal International Normalised Ratio (INR) 1.21 0.8-1.2 sec High Prothrombin time (PT) 15.7 12.3-14.7 sec High Lactate dehydrogenase (LDH) 491 135-225 U/L High Thyroid-stimulating hormone (TSH) 0.222 0.27-4.20 mIU/L Low Adrenocorticotropic hormone (ACTH) 106 ≤50 ng/L Elevated Cortisol (after dexamethasone suppression) 1750 Morning hours (6-10 am): 172-497 nmol, Afternoon hours (4-8 pm): 74.1-286 nmol nmol/L Elevated (failure of suppression) 24-hour urine cortisol (after dexamethasone suppression) 5959.1 <120 nmol/24 hrs nmol/24hr Elevated (failure of suppression) Table 1: Results of blood test at the time of hospitalization. Hypokalemia and high values of adrenocorticotropic hormone and cortisol were confirmed. On examination, the patient's vital signs were as follows: blood pressure was 154/77 mmHg, heart rate of 60 beats per minute, respiratory rate was 18 breaths per minute, oxygen saturation of 98% on room air, and a temperature of 36.7°C. The patient had a typical Cushingoid appearance with a moon face, buffalo hump, purple striae on the abdomen, central obesity, and hyperpigmentation of the skin. Submandibular lymph nodes were enlarged bilaterally. The examination of the submandibular lymph nodes showed a firm, fixed mass extending from the angle of the mandible to the submental space on the left side. Neurological examination showed weakness in both legs bilaterally (strength 3/5) and anosmia (checked by orthonasal smell test). The rest of the neurological exam was normal. Laboratory findings revealed (in Table 1) a marked hypokalemia of 2.49 mmol/L and hyperglycemia of 6.52 mmol/L. The serum cortisol level was elevated at 1587 nmol/L. Serum ACTH levels were raised at 106 ng/L (normal value ≤50 ng/L). Moreover, the high-dose dexamethasone suppression test failed to lower the serum ACTH levels and serum and urine cortisol. Serum cortisol level after the suppression test was 1750 nmol/L, while 24-hour urine cortisol after the test was 5959.1 nmol/24hr. Serum ACTH levels after the test also remained high at 100mg/L. This indicated failure of ACTH suppression by high-dose dexamethasone, which points towards ectopic ACTH production. Other blood tests (complete blood count, liver function tests) were insignificant. A computed tomography scan with contrast (CT scan) of the chest, abdomen, and pelvis, with a special focus on the adrenals, was negative for any malignancy or masses. CT scan of the neck showed bilaterally enlarged submandibular lymph nodes and an enlarged right lobe of the thyroid with nodules. Fine needle aspiration (FNA) of the thyroid nodules revealed a benign nature. Magnetic resonance imaging (MRI) of the brain showed a contrast-enhancing soft tissue lesion (18x18x10mm) in the midline olfactory groove area with extension into the frontal dura and superior sagittal sinus, suggesting recurrence of the previous ONB. There was evidence of previous surgery also. The pituitary gland was normal (Figures 1-2). Figure 1: A brain MRI (T1-weighted; without contrast; sagittal plane) shows a soft tissue lesion located in the midline olfactory groove area. Dural surface with extension into anterior frontal dura. MRI: Magnetic resonance imaging Figure 2: A brain MRI (T2-weighted; without contrast; axial plane) shows a soft tissue lesion located in the midline olfactory groove area. MRI: Magnetic resonance imaging Octreotide scintigraphy showed three focal abnormal uptakes in the submandibular cervical nodes. Additionally, there was a moderate abnormal uptake at the midline olfactory groove with bilateral extension (Figure 3). Figure 3: Whole-body octreotide scan (15 mCi 99mTc-Octreotide IV) demonstrates three focal abnormal uptakes: the largest (5.2 x 2.4 cm) in the left submandibular region, and two smaller ones on the right, suggestive of lymph node uptake. Additional abnormal uptake was seen along the midline of the olfactory groove region with bilateral extension. No other significant abnormal uptake was identified. On microscopic examination, an excisional biopsy after the transcranial resection surgery of the frontal skull base tumor showed nests and lobules of round to oval cells with clear cytoplasm, separated by vascular and hyalinized fibrous stroma (Figures 4A-4B). Tumor cells show mild to moderate nuclear pleomorphism, and fine chromatin (Figure 4C). A fibrillary neural matrix is also present. Some mitotic figures can be seen. Immunohistochemical stains revealed positive staining for synaptophysin (Figure 4D) and chromogranin (Figure 4E). Stains for CK (AE1/AE3), CD45, Desmin, and Myogenin are negative. Immunostaining for ACTH was focally positive (Figure 4F), while the specimen of the cervical lymph nodes showed the same staining, indicating metastases. The cytomorphologic and immunophenotypic features observed are consistent with a Hyams grade II ONB, with ectopic ACTH production. Figure 4: Histopathological and immunohistochemical findings of olfactory neuroblastoma. A (100x magnification) and B (200x magnification) - hematoxylin and eosin (H-E) staining shows cellular nests of round blue cells separated by hyalinized stroma. C (400x magnification) - nuclei show mild to moderate pleomorphism with fine chromatin. D (100x magnification) - an immunohistochemical stain for synaptophysin shows diffuse, strong cytoplasmic positivity within tumor cells. E (200x magnification) - tumor cells are positive for chromogranin. F (400x magnification) - ACTH cytoplasmic expression in tumor cells. ACTH: adrenocorticotropic hormone For his resistant hypokalemia, he had to be given intravenous (IV) and oral potassium chloride (KCL) repeatedly. The patient underwent transcranial resection of the frontal skull base tumor. The patient received cefazolin for seven days, and hydrocortisone for four days. After transcranial resection, his cortisol level decreased to 700 nmol/L. Furthermore, ACTH dropped, and serum potassium also normalized. Subsequently, the patient was transferred to the intensive care unit (ICU) for meticulous monitoring and continued care. In the ICU, the patient developed one episode of a generalized tonic-clonic seizure, which aborted spontaneously, and the patient received phenytoin and levetiracetam to prevent other episodes. A right-sided internal jugular vein and left transverse sinus thrombosis were also developed and treated with enoxaparin sodium. Following surgery, his low potassium levels improved, resulting in an improvement in his limb weakness. His other symptoms also gradually improved after surgery. Three weeks following the primary tumor resection, he underwent bilateral neck dissection with right hemithyroidectomy, for removal of the metastases. The patient opted out of chemotherapy and planned for an international transfer to his home country for further management. Other treatments that he received during hospitalization were ceftriaxone, azithromycin, and Augmentin®. Insulin was used to manage his diabetes, perindopril to regulate his blood pressure, and spironolactone to increase potassium retention. Omeprazole was administered to prevent GI bleeding and heartburn/gastroesophageal reflux disease relief after discharge. Discussion ONB was first described in 1924, and it is a rare neuroectodermal tumor that accounts for 2% of tumors affecting the nasal cavity [11]. Even though ONB has a good survival rate, long-term follow-up is necessary due to the disease's high recurrence rate [2]. ONB recurrence has been approximated to range between 30% and 60% after successful treatment of the primary tumor [12]. Recurrent disease is usually locoregional and tends to have a long interval to relapse with a mean of six years [12]. The first reported case of ectopic ACTH syndrome caused by ONB was in 1987 by M Reznik et al., who reported a 48-year-old woman with ONB who developed a Cushing-like syndrome 28 months before her death [13]. The occurrence of Cushing’s syndrome due to ectopic ACTH can occur either in the initial tumor or even years later during its course or after recurrence [3,6,9,14]. Similar to the case of Abe et al. [3], our patient also presented with muscle weakness due to hypokalemia, which is a feature of Cushing’s syndrome. Hypokalemia is present at diagnosis in 64% to 86% of cases of EAS and is resistant to treatment [9,14], as seen in our case. In our patient, the exact time of development of Cushing’s syndrome could not be ascertained due to the non-availability of previous records. However, according to the patient, he started developing abdominal obesity, pigmentation, and buffalo hump in 2021 about two years after his second surgery for ONB. The distinction between pituitary ACTH and ectopic ACTH involves utilizing CT/MRI of the pituitary, corticotropin-releasing hormone (CRH) stimulation test with petrosal sinus blood sampling, high dose dexamethasone suppression test, and checking serum K+ (more commonly low in ectopic ACTH) [2,15,16]. In our case, a CRH stimulation test was not available but CT/MRI brain, dexamethasone test, low serum potassium, plus the postoperative fall in cortisol levels, all pointed towards an ectopic ACTH source. Conclusions In conclusion, this case highlights the rare association between ONB and ectopic ACTH syndrome, which developed after tumor recurrence. The patient's unique presentation of bilateral lower limb weakness and hypokalemia can cause diagnostic challenges, emphasizing the need for comprehensive diagnostic measures. Surgical intervention proved crucial, with postoperative cortisol values becoming normal, highlighting the efficacy of this approach. The occurrence of ectopic ACTH production in ONB patients, although very rare, is emphasized, so that healthcare professionals who deal with these tumors are aware of this complication. This report contributes valuable insights shedding light on the unique ONB manifestation causing ectopic ACTH syndrome. The ongoing monitoring of the patient's clinical features will further enrich the understanding of the course of this uncommon phenomenon in the medical literature. References Thompson LD: Olfactory neuroblastoma. Head Neck Pathol. 2009, 3:252-9. 10.1007/s12105-009-0125-2 Abdelmeguid AS: Olfactory neuroblastoma. Curr Oncol Rep. 2018, 20:7. 10.1007/s11912-018-0661-6 Abe H, Suwanai H, Kambara N, et al.: A rare case of ectopic adrenocorticotropic hormone syndrome with recurrent olfactory neuroblastoma. Intern Med. 2021, 60:105-9. 10.2169/internalmedicine.2897-19 Yin Z, Wang Y, Wu Y, et al.: Age distribution and age-related outcomes of olfactory neuroblastoma: a population-based analysis. Cancer Manag Res. 2018, 10:1359-64. 10.2147/CMAR.S151945 Platek ME, Merzianu M, Mashtare TL, Popat SR, Rigual NR, Warren GW, Singh AK: Improved survival following surgery and radiation therapy for olfactory neuroblastoma: analysis of the SEER database. Radiat Oncol. 2011, 6:41. 10.1186/1748-717X-6-41 Elkon D, Hightower SI, Lim ML, Cantrell RW, Constable WC: Esthesioneuroblastoma. Cancer. 1979, 44:3-1087. 10.1002/1097-0142(197909)44:3<1087::aid-cncr2820440343>3.0.co;2-a Nieman LK, Biller BM, Findling JW, Newell-Price J, Savage MO, Stewart PM, Montori VM: The diagnosis of Cushing's syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008, 93:1526-40. 10.1210/jc.2008-0125 Chabre O: Cushing syndrome: physiopathology, etiology and principles of therapy [Article in French]. Presse Med. 2014, 43:376-92. 10.1016/j.lpm.2014.02.001 Isidori AM, Lenzi A: Ectopic ACTH syndrome. Arq Bras Endocrinol Metabol. 2007, 51:1217-25. 10.1590/s0004-27302007000800007 Kunc M, Gabrych A, Czapiewski P, Sworczak K: Paraneoplastic syndromes in olfactory neuroblastoma. Contemp Oncol (Pozn). 2015, 19:6-16. 10.5114/wo.2015.46283 Finlay JB, Abi Hachem R, Jang DW, Osazuwa-Peters N, Goldstein BJ: Deconstructing olfactory epithelium developmental pathways in olfactory neuroblastoma. Cancer Res Commun. 2023, 3:980-90. 10.1158/2767-9764.CRC-23-0013 Ni G, Pinheiro-Neto CD, Iyoha E, et al.: Recurrent esthesioneuroblastoma: long-term outcomes of salvage therapy. Cancers (Basel). 2023, 15:1506. 10.3390/cancers15051506 Reznik M, Melon J, Lambricht M, Kaschten B, Beckers A: Neuroendocrine tumor of the nasal cavity (esthesioneuroblastoma). Apropos of a case with paraneoplastic Cushing's syndrome [Article in French]. Ann Pathol. 1987, 7:137-42. Kadoya M, Kurajoh M, Miyoshi A, et al.: Ectopic adrenocorticotropic hormone syndrome associated with olfactory neuroblastoma: acquirement of adrenocorticotropic hormone expression during disease course as shown by serial immunohistochemistry examinations. J Int Med Res. 2018, 46:4760-8. 10.1177/0300060517754026 Clotman K, Twickler MTB, Dirinck E, et al.: An endocrine picture in disguise: a progressive olfactory neuroblastoma complicated with ectopic Cushing syndrome. AACE Clin Case Rep. 2017, 3:278-83. 10.4158/EP161729.CR Chung YS, Na M, Ku CR, Kim SH, Kim EH: Adrenocorticotropic hormone-secreting esthesioneuroblastoma with ectopic Cushing’s syndrome. Yonsei Med J. 2020, 61:257-61. 10.3349/ymj.2020.61.3.257 From https://www.cureus.com/articles/226080-olfactory-neuroblastoma-causing-cushings-syndrome-due-to-the-ectopic-adrenocorticotropic-hormone-acth-secretion-a-case-report?score_article=true#!/

Cushing’s syndrome (CS) secondary to adrenocorticotropic hormone (ACTH) producing tumours is a severe condition with a challenging diagnosis. Ectopic ACTH-secretion often involves neuroendocrine tumours (NET) in the respiratory tract. ACTH-secreting small intestine neuro-endocrine tumours (siNET) are extremely rare entities barely reported in literature. This review is illustrated by the case of a 75-year old woman with fulminant ectopic CS caused by a ACTH-secreting metastatic siNET. Severe hypokalemia, fluid retention and refractory hypertension were the presenting symptoms. Basal and dynamic laboratory studies were diagnostic for ACTH-dependent CS. Extensive imaging studies of the pituitary and thorax-abdomen areas were normal, while [68Ga]Ga-DOTATATE PET-CT revealed increased small intestine uptake in the left iliac fossa. The hypercortisolism was well controlled with somatostatin analogues, after which a debulking resection of the tumour was performed. Pathological investigation confirmed a well-differentiated NET with sporadic ACTH immunostaining and post-operative treatment with somatostatin analogues was continued with favourable disease control. © Acta Gastro-Enterologica Belgica. ABOUT THE CONTRIBUTORS B alliet, c severi, t veekmans, j cuypers, h topal, c m deroose, t roskams, m bex, j dekervel B Alliet Department of Gastroenterology, UZ Leuven, Leuven, Belgium. C Severi Department of Gastroenterology, ZOL, Genk, Belgium. T Veekmans Department of Pathology, UZ Leuven, Leuven, Belgium. J Cuypers Department of Endocrinology, AZ Turnhout, Turnhout, Belgium. H Topal Department of Abdominal Surgery, UZ Leuven, Leuven, Belgium. C M Deroose Department of Nuclear Medicine, UZ Leuven, Leuven, Belgium. T Roskams Department of Pathology, UZ Leuven, Leuven, Belgium. M Bex Department of Endocrinology, UZ Leuven, Leuven, Belgium. J Dekervel Department of Gastroenterology – Digestive Oncology, UZ Leuven, Leuven, Belgium. From https://www.physiciansweekly.com/fulminant-ectopic-cushings-syndrome-caused-by-metastatic-small-intestine-neuroendocrine-tumour-a-case-report-and-review-of-the-literature/

Highlights Phaeochromocytoma with ectopic ACTH secretion. Its clinical presentation is varied, and diagnosis is challenging. Ectopic ACTH secretion from a phaeochromocytoma can rapidly progress to severe Cushing’s syndrome. Removal of the primary tumour often leads to full recovery. Abstract Introduction The occurrence of hypercortisolism resulting from adrenocorticotropic hormone (ACTH)-secreting pheochromocytoma is exceedingly uncommon, with limited documented instances thus far. Presentation of case We present a case of ectopic ACTH-secreting pheochromocytoma in a patient who suffered from severe metabolic disorders. Our clinical case outlines the diagnostic history, preoperative correction of the patient's metabolic disturbances and surgical strategy for management of a rare ectopic ACTH producing pheochromocytoma. Discussion Ectopic adrenocorticotropic hormone-secreting pheochromocytoma displays multifaceted clinical features and requires prompt diagnosis and multidisciplinary management in order to overcome the related severe clinical derangements. Conclusion The combination of biochemical and hormonal testing and imaging procedures is mandatory for the diagnosis of ectopic ACTH secretion, and in the presence of an adrenal mass, the possibility of an ACTH-secreting pheochromocytoma should be taken into account. Keywords Hypokalemia Adrenal gland Pheochromocytoma Ectopic cushing's syndrome Cushing's syndrome 1. Introduction Neuroendocrine tumors such as Pheochromocytoma and paraganglioma (PPGL) are an uncommon occurrence. The prevalence of PPGL has been estimated to be between (2–8)/1 million, with a population rate of 1:2500–1:6500 [1], and it is associated with symptoms such as headache, irregular heartbeats, profuse sweating, high blood pressure, nausea, vomiting, nervousness, irritability, and a sense of imminent mortality [2]. Hypercortisolism is also a rare disorder with an incidence of 5/1 million, <10 % of patients with hypercortisolism are caused by ectopic secretion of ACTH [3], and these are most commonly seen in APUD tumors such as small cell bronchopulmonary carcinoma, pancreatic islet carcinoma, medullary thyroid carcinoma, pheochromocytoma, and melanoma [4]. Tumors that secrete both ACTH and catecholamines are much rarer. Here, we present a case of ectopic ACTH-secreting pheochromocytoma with severe metabolic disorders. The case report is compliant with SCARE Guidelines [5]. 2. Case report The patient is a 46-year-old male who presented to our hospital with recurrent symptoms of pheochromocytoma. He reported that he experienced unexplained symptoms such as panic attacks, headache, sweating, nausea, vomiting, and a feeling of imminent death, which could be alleviated by rest. His blood pressure was around 160–220/110–120 mmHg, and he was taking oral antihypertensive drugs regularly, with poor control of his blood pressure. The patient was admitted with a body temperature of 36.7 °C, heart rate of 130 beats/min, respiratory rate of 20 cycles per minute, blood pressure of 138/88 mmHg, height of 175 cm, weight of 67 kg, Body Mass Index (BMI): 21.88, normal physical examination, emaciated body type, thin subcutaneous fat, self-reported weight loss of 20 kg within 10 months, and history of diabetes mellitus of >1 year. Laboratory tests showed that the blood potassium levels were within the normal range, while the blood sugar and beta-hydroxybutyrate levels were elevated (Table 1). Hormonal analysis showed plasma levels of free catecholamine and its metabolites were much higher than normal, in addition to a severe excess of cortisol secretion with circadian rhythm disorders and elevated serum ACTH (Table 2). Small dose dexamethasone suppression test (1 mg) yielded cortisol levels of over 1750 nmol/L (negative: no decrease in blood cortisol), thus confirming the presence of ACTH-dependent hypercortisolism. The results of electrocardiogram, chest computerized tomography (CT), cardiac ultrasound and thyroid ultrasound showed no obvious abnormality. Enhanced CT of the adrenal glands (Fig. 1) revealed the presence of a right adrenal tumor measuring approximately 5.3 ∗ 4.7 cm. Despite undergoing cranial MRI, no pituitary lesion was detected, thereby ruling out the possibility of Cushing's disease. The patient was further considered for possible ectopic ACTH syndrome and suspected ectopic ACTH-secreting pheochromocytoma. Table 1. Laboratory test results. Laboratory test Result Reference value Unit White blood cell 17.03 3.5–9.5 109/L Red blood cell 5.06 3.8–5.1 1012/L Hemoglobin 147 115–150 g/L Platelets 206 125–350 109/L Glucose 12.13 3.9–6.1 mmol/L β-Hydroxybutyric acid 8.680 0–0.30 mmol/L Creatinine 55.30 40–105 umol/L Calcium 2.47 2.2–2.7 mmol/L Phosphate 1.26 0.85–1.51 mmol/L Potassium 3.66 3.5–5.5 mmol/L Sodium 147.1 137–147 mmol/L Table 2. The patient's adrenal hormone results Empty Cell Preoperative Postoperative Reference value Unit Norepinephrine, free 11,900 118 217–1109 pg/ml Adrenaline, free 3940 <24 <95 pg/ml Dopamine 207 <18 <20 pg/ml Methoxy norepinephrine 4130 87.80 <145 pg/ml Methoxy adrenaline 1850 <12 <62 pg/ml Adrenocorticotropic hormone (8:00) 544 10.60 7.2–63.3 pg/ml Cortisol (8:00) >1750 246.00 166–507 nmol/L Adrenocorticotropic hormone (16:00) 647 33.50 – pg/ml Cortisol (16:00) >1750 536.00 73.8–291 nmol/L Adrenocorticotropic hormone (00:00) 566 – – pg/ml Cortisol (00:00) >1750 – nmol/L Renin 2.82 3.10 2.4–32.8 pg/ml Aldosterone 81.51 73.56 16–160 pg/ml Aldosterone/renin concentration ratio 28.90 23.73 0–25 Download : Download high-res image (184KB) Download : Download full-size image Fig. 1. Adrenal CT showed a 53 ∗ 47 mm mass in the right adrenal gland. In response to the patient's pheochromocytoma symptoms and improve preoperative preparation, we used α-blocker (Phenoxybenzamine 20 mg q8h) to lower blood pressure and increase blood volume, antihypertensive medication (nifedipine 30 mg q12h, olmesartan tablets 20 mg q12h) to assist in lowering blood pressure, and β-blocker (metoprolol 47.5 mg q12h) to control the heart rate. On the 4th day in hospital, the patient was lethargic and had weak limbs. Urgent blood workup showed severe hypokalemia (2.85 mmol/L) as well as hyperglycemia (10.26 mmol/L). Patient was transferred to intensive care to correct intractable hypokalemia and diabetic ketoacidosis. After the patient was transferred to ICU, a deep vein cannulation was performed with intravenous potassium chloride supplementation, and the patient's blood potassium was maintained at normal levels prior to surgery through a large amount of potassium supplementation (Fig. 2A). For diabetic ketoacidosis, insulin administration, rehydration, ketone elimination and other treatments were given and the amount of access was recorded, and it was found that the patient was polyuric, with the highest urine volume of 21,800 ml in a single day (Fig. 2B), and the amount of urine did not decrease by taking oral desmopressin tablets 0.1 mg bid. Download : Download high-res image (255KB) Download : Download full-size image Fig. 2. Changes in blood potassium and urine volume during the patient's hospitalization. A: Blood potassium level. B: Daily urine vlume. Eventually, the patient underwent laproscopic right adrenal tumor resection. Intraoperative changes in blood pressure and heart rate are shown in Fig. 3. On day 1 after surgery, the morning (8:00) ACTH level was 10.60 pg/ml, antihypertensive medications were discontinued, and his blood pressure was 100–120/60–90 mmHg. The patient's daily urine output and blood glucose gradually returned to normal levels after surgery. Pathology (Fig. 4😞 Adrenal pheochromocytoma with ACTH immunopositive staining, cellular heterogeneity was unremarkable, nuclear schizophrenic images were rare, no pericytes, choroidal invasion and necrosis were seen. The patient was discharged from the clinic in a satisfactory condition with adrenal insufficiency compensated by daily intake of Prednisone Acetate Tablets (20 mg), discontinued 6 months after surgery. No signs of recurrence were noted upon frequent follow-up examinations. Download : Download high-res image (295KB) Download : Download full-size image Fig. 3. Changes in patient's intraoperative blood pressure and heart rate. Download : Download high-res image (313KB) Download : Download full-size image Fig. 4. Immunohistochemistry. A: hematoxylin and eosin staining B: ACTH. 3. Discussion We share the management of a patient with ectopic ACTH-secreting pheochromocytoma with severe metabolic disturbances, where, in addition to the rare etiology, perioperative management of the clinical complications of catecholamines and hypercortisolism is very challenging [6]. Patients suffering from ectopic ACTH syndrome caused by pheochromocytoma commonly exhibit severe Cushing's syndrome (CS), significant diabetes mellitus, hypertension, and hypokalemia [7]. Additionally, a retrospective study revealed that the majority of patients presented with Cushing's syndrome [8], whereas another report indicated that only 30 % of patients presented with typical Cushing's syndrome, but weight loss was frequently observed [9]. Our patient's recent weight loss may be attributed to the body's hypermetabolic condition caused by catecholamines. Recent reports claim that catecholamines directly reduce subcutaneous and visceral fat [10]. Rapid onset of cortisolism appears to be a feature of ACTH-secreting pheochromocytomas, because of the rapid onset of severe hypercortisolism, and our patient did not exhibit typical Cushing's symptoms [8]. Despite the absence of typical Cushing-like symptoms, this patient displayed persistent hypokalemia, a prevalent metabolic manifestation of Cushing's syndrome, particularly in ectopic ACTH syndrome, where hypokalemia is observed in 74 %–95 % of patients, in contrast to 10 % of patients with Cushing's disease [11]. Glucocorticoids have the ability to interact with aldosterone receptors, resulting in specific aldosterone-like reactions, while ectopic ACTH syndrome typically generates a higher amount of cortisol compared to Cushing's disease, ultimately causing more pronounced hypokalemia [7]. The perioperative management of patients with ACTH-secreting pheochromocytomas poses a significant challenge due to severe hypokalemia, and our patient's potassium levels remained within the normal range through extensive central venous potassium supplementation, without the need for cortisol secretion inhibition medications. The severity of hypertension in patients with ACTH-secreting pheochromocytomas seems to surpass that of patients with pheochromocytomas alone [12]. Hypercortisolism amplifies catecholamine-induced hypertension [13]. In the case of hypertension in patients with pheochromocytomas, alpha-blockers are favored for reducing blood pressure and enlarging blood volume, while for individuals whose blood pressure is not adequately managed with alpha-blockers alone, a combination of medications is recommended. Proper preoperative readiness for expanding the volume is crucial for a successful surgical procedure. Patients with ACTH-secreting pheochromocytoma have a greater prevalence and intensity of diabetes mellitus compared to those with pheochromocytoma alone [14], and our patient displayed a combination of severe diabetes mellitus and ketoacidosis. Insulin exhibits swift action and adaptable dosage, effectively averting hypoglycemia and effectively addressing hyperglycemia, rendering it the preferred medication for regulating blood glucose levels in individuals with ectopic CS [6]. Managing the water-electrolyte balance in this patient proved to be an arduous task, and the diabetes insipidus may have been one of the complications, with a maximum urine output of 21,800 ml in a single day (Fig. 2), and we hold the belief that the patient's diabetes insipidus is caused by a range of factors, such as hypokalemia, hypercortisolism, and severe diabetes mellitus. Indeed, hypokalemia may cause renal impairment, which reduces the ability to concentrate urine and lack of response to antidiuretic hormone (ADH), leading to nephrogenic diabetes insipidus [15]. Cortisol increases renal plasma flow and glomerular filtration rate, and also inhibits the secretion of antidiuretic hormone, leading to neurogenic diabetes insipidus [16]. For hypercortisolism, surgery to target the cause is the first-line treatment, and surgical removal of primary tumor may lead to 40 % radical treatment and 80 % complete remission of ectopic ACTH syndrome [17]. 4. Conclusion Preoperative diagnosis and management of pheochromocytoma, an extremely rare cause of ectopic ACTH syndrome, is challenging. Proper preoperative recognition of complications of both hypercortisolism and catecholamines excess is the key to prevent the morbidity and mortality of an ACTH-producing pheochromocytoma. If diagnosed successfully and managed intensively, they are curable. Consent Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request. Ethical approval Shandong Provincial Hospital Affiliated to Shandong First Medical University does not require ethical approval for publication of case reports. Signed consent from the patient has been received. Funding No funding was received for this research. Author contribution Shangjian Li: study concept or design, data collection, data analysis or interpretation, writing the paper Xudong Guo: study concept or design, data collection, data analysis or interpretation, writing the paper Hanbo Wang: study concept or design, data analysis or interpretation Ni Suo: study concept or design, data analysis or interpretation Xiuqing Mi: study concept,data collection Shaobo Jiang: study concept or design, data analysis or interpretation, writing the paper Guarantor Shangjian Li Xudong Guo Shaobo Jiang Conflict of interest statement All authors declare no conflict of interest. Acknowledgements None. References [1] A. Jain, R. Baracco, G. Kapur Pheochromocytoma and paraganglioma-an update on diagnosis, evaluation, and management Pediatr. Nephrol., 35 (2020), pp. 581-594 View article CrossRefView in ScopusGoogle Scholar [2] F.A. Farrugia, A. Charalampopoulos Pheochromocytoma Endocr. 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Autophagic degradation of aquaporin-2 is an early event in hypokalemia-induced nephrogenic diabetes insipidus Sci. Rep., 5 (2015), Article 18311 View PDF This article is free to access. View in ScopusGoogle Scholar [16] M.M. Hammami, N. Duaiji, G. Mutairi, et al. Case report of severe Cushing’s syndrome in medullary thyroid cancer complicated by functional diabetes insipidus, aortic dissection, jejunal intussusception, and paraneoplastic dysautonomia: remission with sorafenib without reduction in cortisol concentration BMC Cancer, 15 (2015), p. 624 View PDF This article is free to access. View in ScopusGoogle Scholar [17] A. Ferriere, A. Tabarin Cushing’s syndrome: treatment and new therapeutic approaches Best Pract. Res. Clin. Endocrinol. Metab., 34 (2020), Article 101381 View PDFView articleView in ScopusGoogle Scholar From https://www.sciencedirect.com/science/article/pii/S2210261224001226

Highlights EAS should be considered in patients presenting with rapid progression of ACTH-dependent hypercortisolism causing severe clinical and metabolic abnormalities. Ectopic ACTH secretion by a pheochromocytoma should be suspected in cases of ACTH-dependent Cushing syndrome in the presence of an adrenal mass. If required, medical management with steroidogenesis inhibitors can be initiated at the time of EAS diagnosis to control clinical and metabolic derangements associated with severe hypercortisolemia In patients with ACTH-dependent Cushing syndrome from an ectopic source, inhibiting steroidogenesis should be reserved for cases where the initial diagnosis is unclear or patients who are not suitable candidates for surgery. Unilateral adrenalectomy is indicated in the management of ACTH/CRH-secreting pheochromocytomas and is typically curative. Catecholamine blockade should be started prior to surgical removal of catecholamines-secreting pheochromocytomas. A multidisciplinary approach is required to diagnose and manage this condition. Abstract Background/Objective Ectopic co-secretion of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) in silent (i.e., noncatecholamine-secreting) pheochromocytoma is a rare cause of Cushing Syndrome (CS). Case Report A 57-year-old woman rapidly developed hypercortisolism, clinically manifesting as fatigue, muscle weakness, weight gain, and worsening hypertension, and biochemically characterized by hypokalemia and marked elevation of serum cortisol and plasma ACTH. This acute presentation suggested a diagnosis of ectopic ACTH syndrome (EAS). Imaging studies revealed a right adrenal mass that enhanced after administration of the radioisotope 68Ga-DOTATATE. Plasma metanephrines were normal in two separate measurements. The possibility of a silent pheochromocytoma was considered. After controlling her hypercortisolism with metyrapone and surgical preparation with alpha blockade, the patient underwent elective right adrenalectomy. Pathology revealed a pheochromocytoma that stained focally for ACTH and CRH. Postoperatively, cortisol levels normalized, the hypothalamic–pituitary–adrenal (HPA) axis was not suppressed, and clinical symptoms from hypercortisolism abated. Discussion Patients who exhibit a rapid progression of ACTH-dependent hypercortisolism should be screened for ectopic ACTH syndrome (EAS). The use of functional imaging radioisotopes (such as gallium DOTA-peptides), improves the detection of ACTH-secreting tumors. Preoperative treatment with steroidogenesis inhibitors helps control clinical and metabolic derangements associated with severe hypercortisolemia, while alpha blockade prevents the onset of an adrenergic crisis. Conclusion We present a rare case of EAS due to a silent pheochromocytoma that co-secreted ACTH and CRH. Pheochromocytoma should be considered in patients with EAS who have an adrenal mass even in the absence of excessive catecholamine secretion. Key words ectopic ACTH syndrome Cushing Syndrome non-catecholamine-secreting pheochromocytoma Abbreviations EAS ectopic ACTH syndrome CS Cushing Syndrome CRH corticotropin-releasing hormone ACTH adrenocorticotropic hormone DHEA-S dehydroepiandrosterone sulfate UFC urine free cortisol PRA plasma renin activity Introduction Cushing Syndrome (CS) is rare, with an estimated incidence of 0.2-5.0 per million people per year, and prevalence of 39-79 per million (1). Ectopic ACTH Syndrome (EAS), a type of CS originating from extra-pituitary ACTH-secreting tumors, is uncommon. The prevalence of CS due to ACTH-secreting adrenal medullary lesions is not well established. However, EAS is observed in approximately 1.3% of all identified cases of pheochromocytoma (2). Recognizing EAS can be challenging due to its rarity, leading to delayed diagnosis. Neuroendocrine neoplasms can produce CRH, which can lead to the secretion of ACTH by the pituitary. In certain cases, co-secretion of ACTH and CRH by an adrenal neoplasm has been observed. Only two published cases have provided definitive biochemical and immunohistochemical evidence of exclusive CRH secretion (3). Case Report A 57-year-old woman with a history of well-controlled hypertension sought care due to a two-month history of 60 lb weight gain, facial rounding, easy bruising, muscle weakness, lower extremity edema and acne. Her blood pressure control had worsened, and laboratory tests showed a markedly low serum potassium level of 1.8 mmol/L while taking hydrochlorothiazide. To manage her blood pressure, she was prescribed a calcium channel blocker, an angiotensin receptor blocker, and potassium supplements. However, her symptoms worsened, and she was referred to our emergency department. Blood pressure at presentation to our hospital was 176/86 mmHg. She had characteristic features of CS, including face rounding, supraclavicular fullness, dorsocervical fat accumulation, pedal edema, oral candidiasis, multiple forearm ecchymoses, and acneiform skin eruptions. No visible abdominal striae were present. She had no family history of pheochromocytoma, or multiple endocrine neoplasia type 2. Serum cortisol level was 128 mcg/dL (normal range: 4.6-23.4) at 5 PM, with an ACTH level of 1055 pg/mL (normal range: 6-50); serum DHEA-S level was elevated at 445 mcg/dL (normal range: 8-188). Her 24-hour urine cortisol was at 12,566 mcg (normal range: 4.0-50.0). Plasma metanephrines were normal at <25 pg/mL (normal range: <57), and plasma normetanephrine was 44 (normal range: <148). A second plasma metanephrine measurement showed similar results. Serum aldosterone level and plasma renin activity were low at 2 ng/dL (normal range: 3-16) and 0.11 ng/mL/h (normal range: 0.25-5.82), respectively. Dopamine and methoxytyramine levels were not measured. An abdominal CT revealed a 4.8 x 4.5 x 5 cm right heterogeneously enhancing adrenal mass with a mean Hounsfield Unit of 68 in the non-contrast phase, and an absolute percentage washout of 30% (Fig 1A). The left adrenal gland appeared hyperplastic (Fig 1B). An Octreoscan, which was the in-hospital available nuclear medicine imaging modality, confirmed a 5.1 cm adrenal mass that was mild to moderately avid, with diffuse bilateral thickening of the adrenal glands and no other focal radiotracer avidity. A pituitary MRI did not show an adenoma, and EAS was suspected. Further evaluation with 68Ga-DOTATATE PET/CT (Fig 2) performed after her admission demonstrated an avid right adrenal mass consistent with a somatostatin receptor-positive lesion. No other suspicious tracer uptake was detected. These findings were consistent with a neuroendocrine tumor, such as pheochromocytoma. Download : Download high-res image (261KB) Download : Download full-size image Fig. 1. Preoperative abdominal computed tomography scan showing a 4.8 x 4.5 x 5 cm right heterogeneously enhancing adrenal mass with irregular borders (A) and a hyperplastic left adrenal gland (B). Download : Download high-res image (219KB) Download : Download full-size image Fig 2. 68Ga-DOTATATE PET/CT showing an avid right adrenal mass. To control her symptoms while undergoing workup, the patient received oral metyrapone 500 mg thrice daily and oral ketoconazole 200 mg twice daily. Ketoconazole was stopped due to an increase in transaminases. The dosage of metyrapone was increased to 500 mg four times daily and later decreased to alternating doses of 250 mg and 500 mg four times daily. Within 3 weeks of starting medical therapy, serum cortisol level normalized at 20 mcg/dL. The 24-hour UFC improved to 246.3 mcg/24h. She experienced gradual improvement in facial fullness, acne, and blood pressure control. The possibility of a silent pheochromocytoma was considered, and a-adrenergic blockade with doxazosin 1 mg daily was started 1 month prior surgery. She underwent surgery after two months of metyrapone therapy. With an unclear diagnosis and a large, heterogeneous adrenal mass, the surgical team elected to perform open adrenalectomy for en bloc resection due to concerns for an adrenal malignancy. The tumor was well-demarcated and did not invade surrounding structures (Figure 3A). H&E-stained sections showed classic morphologic features of a pheochromocytoma (Figure 3B), with immunohistochemistry demonstrating strong immunoreactivity for synaptophysin and chromogranin, and negative SF- I and inhibin stains excluding an adrenal cortical lesion. The sections analyzed by QuPath (4) revealed that approximately 4% of ce11s were ACTH cells, often found in isolation, and had a clear, high signal-to-noise staining (Figure 3C). CRH cells were less prevalent, comprising about 2.4% of the total analyzed cells, and tended to cluster together (Figure 3D). These cells had more background staining, resulting in a lower signal- to-noise ratio. Download : Download high-res image (663KB) Download : Download full-size image Figure 3. Gross and Histopathological analysis of the patient’s pheochromocytoma. (A) Image of the gross excised specimen. (B) H&E staining (200x final magnification) demonstrates prominent vascularity and cells with finely granular, eosinophilic cytoplasm and salt-and-pepper chromatin. (C) ACTH staining (200x final magnification) shows clear and isolated positive cells, representing about 4.0% of the section analyzed by QuPath. (D) CRH staining (200x final magnification) reveals tight clusters of positive cells, accounting for 2.4% of the total cells. Positive (human placenta and hypothalamus) and negative (thyroid gland) control tissues performed as expected (data not shown). The patient's postoperative recovery was uneventful, with a short course of hydrocortisone which was stopped 1 week after surgery after HPA axis evaluation showed normal results. After one month, hypercortisolism had resolved, as shown by a normal 24-hour UFC at 28 mcg. Administration of dexamethasone at 11 PM resulted in suppression of morning cortisol to 0.8 and 0.6 mcg/dL 1 and 7 months after surgery, respectively. Her liver function tests normalized, and blood pressure was well-controlled with amlodipine 10 mg daily and losartan 100 mg daily. Genetic testing for pheochromocytoma predisposition syndromes is currently planned. Discussion EAS accounts for 10-20% of cases of ACTH-dependent CS (5). This condition can be caused by several neuroendocrine neoplasms that produce bioactive ACTH (6) In the literature, we have found 99 documented cases of EAS caused by a pheochromocytoma. Of these, 93% showed ACTH expression. Only two cases have been reported with dual staining of ACTH and CRH (7). Exclusive CRH production has only been reported in two cases (8:9). However, the true prevalence of CRH-producing pheochromocytomas might be underestimated, as most cases testing for CRH expression was not performed. Although the clinical presentation of EAS may be highly variable, there is often a rapid onset of hypercortisolism accompanied by severe catabolic symptoms. The diagnostic process should focus on identifying the location of a potential neuroendocrine neoplasm responsible for the ACTH secretion. Sometimes the peripheral origin of ACTH must be confirmed by inferior petrosal sinus sampling (IPSS). In this case, given the clinical presentation consistent with EAS, negative pituitary MRI, and the presence of an adrenal mass that needed to be removed independently, IPSS was not performed. Neuroendocrine neoplasms express somatostatin receptors on their surface, which allow functional imaging using [11 lln]-pentetreotide (Octreoscan). However, Octreoscan has a low sensitivity in detecting occult EAS. In cases where the tumor is in the abdomen and pelvis, Octreoscan has limited utility in locating the source of ACTH (10). This increased risk of false negatives is caused by physiological tracer uptake by the liver, spleen, urinary tract, bowel, and gallbladder. The use of Gallium-68 labeled somatostatin receptor ligands (PET/CT 68Ga-DOTATATE) is more effective in detecting somatostatin receptors (SSTR2) than [11lln]-pentetreotide due to its higher spatial resolution and affinity (11)_ This test was performed after discharge form the hospital to rule out the presence of a second, smaller neuroendocrine tumor that the Octreoscan might have missed. A new molecular imaging technique targeting CRH receptors (68Ga CRH PET/CT) has shown potential in identifying tumors expressing CRH, but its availability remains limited (12). In our patient's case, both the Octreoscan and 68Ga- DOTATATE successfully identified the adrenal tumor as a potential ACTH/CRH secretion source. According to relevant guidelines, presurgical adrenergic blockade is recommended for patients with biochemical evidence of catecholamine excess (13, 14). Conversely, silent pheochromocytomas can generally be operated without alpha blockade (15). Despite this, we opted to administer pre-operative alpha blockade as a precautionary measure for this patient. Pathology examination confirmed the diagnosis of pheochromocytoma. ACTH and CRH staining demonstrated that clear and significant populations of two separate ACTH and CRH positive cells were present in the excised pheochromocytoma. ACTH/CRH cells were dispersed throughout various regions of the pheochromocytoma rather than being well-defined, separate histological entities. As a result, there is no indication that this resulted from collision tumors, but rather random mutation and expansion of tumor cells into ACTH or CRH secreting cells. These results have limitations, including variation in ACTH and CRH expressing regions due to tumor heterogeneity, nonspecific binding of polyclonal antibodies, and normal low-rate false negative/positive detection using QuPath. Post-surgical normal HPA activity was likely due to the de-suppression of the HPA axis by medical therapy, but it may also be explained by chronic stimulation of corticotroph cells induced by ectopic CRH secretion. The standard approach to managing EAS involves surgical intervention. However, surgery may not be a viable option in cases where the source of ACTH production is unknown. Medical therapy to reduce or block excess cortisol can be used in such circumstances. Conclusions In conclusion, a pheochromocytoma causing EAS should be considered even in the absence of elevated plasma metanephrines. These tumors may simultaneously express ACTH and CRH.CRH. References 1 C. Steffensen, A.M. Bak, K. Zøylner Rubeck, J.O.L. Jørgensen Epidemiology of Cushing’s syndrome Neuroendocrinology, 92 (2010), pp. 1-5 View PDF This article is free to access. CrossRefView in ScopusGoogle Scholar 2 H. Falhammar, J. Calissendorff, C. Höybye Frequency of Cushing’s syndrome due to ACTH-secreting adrenal medullary lesions: a retrospective study over 10 years from a single center Endocrine, 55 (2020), pp. 296-302 Google Scholar 3 K.B. Lois, A. Santhakumar, S. Vaikkakara, S. Mathew, A. Long, S.J. Johnson, et al. Phaeochromocytoma and ACTH-dependent Cushing’s syndrome: Tumour CRF secretion can mimic pituitary Cushing’s disease Clin Endocrinol (Oxf), 84 (2016), pp. 177-184 View article CrossRefView in ScopusGoogle Scholar 4 P. Bankhead, M. Loughrey, J. Fernandez, Y. Dombrowski, D. Mcart, P. Dunne, et al. QuPath: Open source software for digital pathology image analysis Sci. Rep, 7 (2017), pp. 1-7 Google Scholar 5 M. Savas, S. Mehta, N. Agrawal, E.F.C. van Rossum, R.A. Feelders Approach to the Patient: Diagnosis of Cushing Syndrome J Clin Endocrinol Metab, 107 (2022), pp. 3162-3174 View article CrossRefView in ScopusGoogle Scholar 6 A.M. Isidori, G.A. Kaltsas, C. Pozza, V. Frajese, J. Newell-Price, R.H. Reznek, et al. Extensive clinical experience - The ectopic adrenocorticotropin syndrome: Clinical features, diagnosis, management, and long-term follow-up J Clin Endocrinol Metab, 91 (2006), pp. 371-377 View article CrossRefView in ScopusGoogle Scholar 7 P.F. Elliott, T. Berhane, O. 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Tabarin Management of endocrine disease: Cushing’s syndrome due to ectopic ACTH secretion: an expert operational opinion Eur. J. Endocrinol, 182 (2020), pp. 29-58 View article CrossRefGoogle Scholar 11 A.M. Isidori, E. Sbardella, M.C. Zatelli, M. Boschetti, G. Vitale, A. Colao, et al. Conventional and Nuclear Medicine Imaging in Ectopic Cushing’s Syndrome: A Systematic Review J Clin Endocrinol Metab, 100 (2015), pp. 3231-3244 View article CrossRefView in ScopusGoogle Scholar 12 R. Walia, R. Gupta, A. Bhansali, R. Pivonello, R. Kumar, H. Singh, et al. Molecular Imaging Targeting Corticotropin-releasing Hormone Receptor for Corticotropinoma: A Changing Paradigm J. Clin. Endocr, 106 (2021), pp. 1816-1826 View article CrossRefGoogle Scholar 13 J.W.M. Lenders, M.N. Kerstens, L. Amar, et al. Genetics, diagnosis, management and future directions of research of phaeochromocytoma and paraganglioma: a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension J Hypertens, 38 (2020), pp. 1443-1456 View article CrossRefView in ScopusGoogle Scholar 14 D. Taïeb, G.B. Wanna, M. Ahmad, C. Lussey-Lepoutre, N.D. Perrier, S. Nölting, et al. Clinical consensus guideline on the management of phaeochromocytoma and paraganglioma in patients harbouring germline SDHD pathogenic variants Lancet Diabetes Endocrinol, 11 (2023), pp. 345-361 View PDFView articleView in ScopusGoogle Scholar 15 K. Pacak Preoperative management of the pheochromocytoma patient J Clin Endocrinol Metab, 92 (2007), pp. 4069-4079 View article CrossRefView in ScopusGoogle Scholar Cited by (0) Sources of support: None Permission in the form of written consent from patient for use of actual test results was obtained. Cushing in silent pheochromocytoma Clinical Relevance This case highlights the importance of considering ectopic ACTH secretion by a pheochromocytoma in patients presenting with rapid progression and considerable clinical hypercortisolism concomitant with an adrenal mass and elevated plasma ACTH. This represents an unusual manifestation of a specific subtype of ACTH/CRH-secreting pheochromocytoma that did not exhibit catecholamine secretion The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper ∗ These 2 authors contributed equally to this work From https://www.sciencedirect.com/science/article/pii/S2376060524000075

Abstract Ectopic adrenocorticotropin (ACTH)-secreting tumors are among the causes of ACTH-dependent Cushing syndrome. When surgical resection of the primary lesion is not feasible, medications such as metyrapone, mitotane, and ketoconazole have been used to control hypercortisolism. This report presents a case treated with the novel drug osilodrostat, wherein the patient's adrenal glands exhibited shrinkage following the initiation of this drug. The case involves a 68-year-old man diagnosed with small cell lung cancer and ectopic ACTH-producing Cushing syndrome. Initially, metyrapone was administered to manage hypercortisolism, but its effect proved insufficient. Subsequently, osilodrostat was initiated while gradually decreasing metyrapone, leading to full suppression of blood cortisol levels. With continued osilodrostat treatment, the adrenal glands reduced in size, suggesting the potential to reduce the osilodrostat dosage. ectopic ACTH-producing tumor, Cushing syndrome, osilodrostat, adrenal shrinkage Issue Section: Case Report Introduction Ectopic adrenocorticotropin (ACTH)-secreting tumors represent a rare cause of Cushing syndrome, with an estimated annual incidence of 2 or 3 cases per 1 000 000 (1). Cushing syndrome is categorized into ACTH-independent and ACTH-dependent forms. Ectopic ACTH-dependent Cushing syndrome arises from autonomous ACTH secretion by tumors located outside the pituitary gland, comprising approximately 15% of Cushing syndrome cases (1). Notably, small cell carcinomas of the lung are the most common cause of biochemical hypercortisolism (1). Treatment of ectopic ACTH-secreting tumors typically necessitates primary tumor removal, chemotherapy, radiation therapy, and somatostatin analogues (1). Alongside surgical intervention, medications such as metyrapone, mitotane, and ketoconazole have been employed to reduce blood cortisol levels. However, metyrapone's limitations in terms of its potency and dosing frequency have prompted the search for a more effective drug. Osilodrostat has emerged as a promising option for managing Cushing syndrome. It inhibits the enzyme 11β-hydroxylase, which converts 11-deoxycorticosterone (DOC) to corticosterone and 11-deoxycortisol (11-DOF) to cortisol (2). Osilodrostat has a longer biological half-life than metyrapone, allowing for once-daily or twice-daily dosing. Evidently, osilodrostat possesses superior potency against 11β-hydroxylase (2). Case reports suggest that osilodrostat rapidly controls blood cortisol levels in patients with ectopic ACTH-producing tumors. The dosage of osilodrostat typically commences at 2 mg and is gradually adjusted based on cortisol levels and patient response. Although some cases have seen an increase to more than 10 mg initially, the dosages are eventually reduced to 1 to 5 mg. This case presents a unique scenario in which the patient's adrenal glands shrank during osilodrostat treatment, enabling dosage reduction. Case Presentation A 68-year-old man presented to our hospital with complaints of enlarged right hilar lymph nodes, fever, back pain, dizziness, and diarrhea. His height was 171.0 cm, and his weight was 63.1 kg. His vital signs were as follows: heart rate of 102 beats/min and blood pressure of 181/86 mm Hg. He did not have any cushingoid features. A comprehensive evaluation, including blood tests and a computed tomography (CT) scan of the chest and abdomen, was conducted. His blood tests showed hypokalemia and hyperglycemia. CT revealed the presence of a tumor in the right hilar region, along with swelling of the mediastinal and right supraclavicular lymph nodes and enlargement of the bilateral adrenal glands (Fig. 1A-1C). Tumor markers such as neuron specific enolase and pro–gastrin-releasing peptide were markedly elevated; thus, small cell lung cancer was suspected (details are shown in Table 1). Figure 1. Open in new tabDownload slide Progress of lung tumor and adrenal grand in computed tomography. Upper row (A, D, G): progression of small cell lung cancer. There were no changes in the progress. The density in HU of the lung cancer was 31 on day 1, 40 on day 58, and 34 on day 128. Middle row (B, E, H): progression of the size of the adrenal grand. The adrenal grand progressively shrank. Lower row (C, F, I): Each volume of the right adrenal gland was 11.7 mL on day 1, 7.5 mL on day 58, and 4.4 mL on day 128. Each volume of the left adrenal gland was 14.2 mL on day 1, 8.8 mL on day 58, and 4.9 mL on day 128. The density of the right adrenal gland was 30 HU on day 1, 13 HU on day 58, and 30 HU on day 128. The density of the left adrenal gland was 31 HU on day 1, 18 HU on day 58, and 19 HU on day 128. Table 1. Laboratory data on administration Blood tests Results Reference ranges Red blood cell 4.0 10^12/L 4.35-5.55 10^12/L 400 10^4/mcL 435-555 10^4/mcL White blood cell 8.7 10^12/L 3.3-8.6 10^12/L 87 10^4/mcL 33-86 10^4/mcL Differential count  Neutrophils 91.1%  Lymphocytes 6.0%  Eosinophils 0.0% BUN 6.8 mmol/L 2.9-7.1 mmol/L 19 mg/dL 8.0-20 mg/dL Creatinine 72.5 mcmol/L 57.5-94.6 mcmol/L 0.82 mg/dL 0.65-1.07 mg/dL eGFRCre 72 mL/min/1.73 m2 >90 mL/min/1.73 m2 Sodium 152 mmol/L 138-145 mmol/L 152 mEq/L 138-145 mEq/L Chloride 97 mmol/L 101-108 mmol/L 97 mEq/L 101-108 mEq/L Potassium 1.6 mmol/L 3.6-4.8 mmol/L 1.6 mEq/L 3.6-4.8 mEq/L Calcium 2.00 mmol/L 2.20-2.52 mmol/L 8.0 mg/dL 8.8-10.1 mg/dL Blood glucose 15.1 mmol/L 3.9-6.9 mmol/L 272 mg/dL 70-125 mg/dL HbA1c 52 mmol/mol 27-44 mmol/mol 6.9% 4.6%-6.2% ACTH 170 pmol/L 1.6-14.0 pmol/L 770 pg/mL 7.2-63.3 pg/mL Cortisol 2436 nmol/L 196-541 nmol/L 88.3 mcg/dL 7.1-19.6 mcg/dL DHEA-S 10.43 mcmol/L 0.35-7.15 mcmol/L 385 mcg/dL 13-264 mcg/dL SCC 1.7 mcg/L <2.3 mcg/L 1.7 ng/mL <2.3 ng/mL CYFRA 4.2 mcg/L <3.5 mcg/L 4.2 ng/mL <3.5 ng/mL Pro GRP 147 204 ng/L <81 ng/L 147 204 pg/mL <81 pg/mL NSE 205 mcg/L <12 mcg/L 205 ng/mL <12 ng/mL Abnormal values are shown in bold font. Values in the upper row are International System of Units (SI). Abbreviations: ACTH, adrenocorticotropin; BUN, blood urea nitrogen; CYFRA, cytokeratin 19 fragment; DHEA-S, dehydroepiandrosterone sulfate; eGFRCre, estimated glomerular filtration rate from creatinine; HbA1c, glycated hemoglobin A1c; NSE, neuron specific enolase; Pro GRP, pro–gastrin-releasing peptide; SCC, squamous cell carcinoma antigen. Open in new tab Diagnostic Assessment Although his physical findings did not include cushingoid features, the patient's severe hypokalemia, hypertension, and hyperglycemia and the existence of small cell lung cancer indicated that he had ectopic Cushing syndrome due to small cell lung cancer. Next, we examined his plasma ACTH and serum cortisol levels. Both were markedly elevated. Based on the CT scan and blood test data, there was a strong suspicion of ectopic ACTH-producing small cell lung cancer. Pituitary magnetic resonance imaging could not detect obvious tumors in the seller turcica within the visible range. Diagnostic tests for Cushing disease, such as the corticotropin-releasing hormone (CRH) challenge test and arginine vasopressin challenge test, are needed to definitively diagnose ectopic Cushing syndrome. However, we determined that the hypercortisolism should be corrected as soon as possible. A needle biopsy confirmed the lung tumor as small cell carcinoma on day 10. Immunohistochemical analysis revealed the tumor's negativity for chromogranin A, ACTH, and CRH but positivity for proopiomelanocortin (POMC), indicating its potential to produce pro-big ACTH and result in ectopic Cushing syndrome (Fig. 2). Figure 2. Open in new tabDownload slide Immunostaining of the small cell lung cancer. Figures show each immunostaining analysis: A, chromogranin A; B, adrenocorticotropin (ACTH); C, corticotropin-releasing hormone (CRH); D, proopiomelanocortin (POMC). Chromogranin A, ACTH, and CRH are negative in small cell lung cancer, but POMC is positive. This means that small cell lung cancer produces big-ACTH and can result in ACTH-dependent Cushing syndrome. Treatment Without confirming the diagnosis, we initiated the administration of metyrapone at a dose of 500 mg per day since we were familiar with metyrapone rather than osilodrostat. The dose of metyrapone was gradually increased, reaching 2000 mg per day by day 7. An overview of the clinical course is depicted in Fig. 3. Initially, the cortisol level was extremely high, so we did not consider the replacement of any steroids. Subsequently, we used hydrocortisone with metyrapone osilodrostat from day 10. Chemotherapy with etoposide and carboplatin was also started on day 10. Figure 3. Open in new tabDownload slide Changes of adrenocorticotropin (ACTH) and cortisol during metyrapone and osilodrostat, and chemotherapy. Cortisol was suppressed following an increase in the metyrapone and osilodrostat dosage. ACTH was not suppressed after chemotherapy for small cell lung cancer. As 2000 mg of metyrapone failed to sufficiently lower the patient’s serum cortisol level and metyrapone needed to be taken 6 times a day, we introduced osilodrostat at a daily dose of 1 mg starting from day 25. With close monitoring of the patient's serum cortisol and plasma ACTH levels, we gradually increased the osilodrostat dose to 20 mg per day while concurrently decreasing the metyrapone dose. This approach resulted in full suppression of the serum cortisol levels, enabling the discontinuation of metyrapone 20 days after the initiation of osilodrostat. Outcome and Follow-up Subsequently, we gradually decreased the dose of osilodrostat while following the patient's serum cortisol levels (see Fig. 3). Sixty-six days after the initiation of osilodrostat treatment, the patient was successfully maintained on a reduced daily dose of 1 mg without any increase in serum cortisol levels. A plain CT scan conducted after 33 days of osilodrostat treatment demonstrated that the primary lung tumor had somewhat decreased in size, but the density of lung cancer ranged from 30 to 40 HU, which indicated that there was no necrotic change in his lung cancer (Fig. 1D). The scan also revealed a slight reduction in the volume of the bilateral adrenal glands compared to that on day 1 (Fig. 1E and 1F). The patient was readmitted on day 91 for chemotherapy due to small cell lung cancer. Osilodrostat administration was discontinued after day 128. However, the patient's serum cortisol level remained below 4.0 mcg/dL (110 nmol/L). A plain CT scan on day 128 showed a marked reduction in the volume of the bilateral adrenal glands (Fig. 1H and 1I). The patient died of small cell lung cancer on day 143. We analyzed the adrenal steroid profile using residual serum samples on day 48 by liquid chromatography–mass spectrometry. Serum DOC and 11-DOF levels were elevated above the normal range (Table 2). This means that bioactive ACTH was definitely present in excess in the patient's serum, and his adrenal glands were stimulated. We also measured the plasma ACTH using test kits provided by Roche and Tosoh Corporation using residual plasma samples on day 132. The Tosoh test kit has a higher detection sensitivity for pro-ACTH than that of Roche. The ACTH levels were 924 pg/mL (203 pmol/L) and 1257 pg/mL (277 pmol/L), respectively. These results indicate that while some pro-ACTH was present in the patient's plasma, mature ACTH was also present to some extent. Table 2. Hormone levels on day 48 Hormone tested Results Reference ranges ACTH 142 pmol/L 1.6-14.0 pmol/L 646 pg/mL 7.2-63.3 pg/mL Cortisol 41.4 nmol/L 196-541 nmol/L 1.5 mcg/dL 7.1-19.6 mcg/dL DOC 2.18 nmol/L 0.24-0.85 nmol/L 0.72 ng/mL 0.08-0.28 ng/mL 11-DOF 4.34 nmol/L 0.12-3.35 nmol/L 1.50 ng/mL 0.04-1.16 ng/mL Abnormal values are shown in bold font. Values in the upper row are International System of Units (SI). Abbreviations: 11-DOF, 11-deoxycortisol; ACTH, adrenocorticotropin; DOC, 11-deoxycorticosterone. Open in new tab Discussion In our case, we observed 2 significant aspects. First, the patient's adrenal glands exhibited shrinkage despite the plasma ACTH levels not decreasing. Second, the osilodrostat dose was reduced while the adrenal glands shrank. Our search for publications on osilodrostat and ACTH-dependent Cushing syndrome yielded 57 relevant articles as of May 23, 2023, with 47 cases of ACTH-dependent Cushing syndrome, including 38 cases of ectopic ACTH-producing tumors and 9 cases of Cushing disease (3‐10). Thirty-seven out of 47 cases with ACTH-dependent Cushing syndrome were managed with osilodrostat monotherapy, while the remaining 10 patient cases received a combination of osilodrostat, ketoconazole, and cabergoline, among other drugs. In the 37 cases of osilodrostat monotherapy, 2 different strategies for initiating osilodrostat were observed: the titration strategy and the block and replacement with hydrocortisone strategy (see Fig. 4). Twenty-two of 37 cases received the titration strategy, starting with a low initial dose of 1 to 10 mg daily, with only 2 cases initially starting with a higher initial dose (20 mg daily). Twelve patients initially treated with the titration strategy transitioned to the block and replacement strategy during follow-up. On the other hand, 15 of 37 patient cases received the block and replacement strategy, with initial osilodrostat doses varying from 2 to 60 mg daily, supplemented with hydrocortisone from the outset. In our patient case, osilodrostat was initiated in combination with metyrapone but was subsequently switched to monotherapy, with the dose titrated up to 20 mg daily and then tapered to 1 mg. Figure 4. Open in new tabDownload slide Reported strategy of treatment with osilodrostat. Thirty-seven patients received osilodrostat monotherapy. Twenty-two cases had a titration strategy. Twelve of 22 patient cases with a titration strategy were switched during follow-up to a block and replacement strategy. Fifteen patient cases had a block and replacement strategy initially. Notably, none of the 47 cases of ACTH-dependent Cushing syndrome obtained from PubMed mentioned changes in adrenal gland size. Although metyrapone and osilodrostat both attenuate 11β-hydroxylase enzymatic activity, metyrapone-induced adrenal shrinkage has not been reported. Therefore, the inhibition of 11β-hydroxylase by osilodrostat is unlikely to be the cause of the adrenal gland size reduction. The mechanism by which osilodrostat reduces adrenal volume remains unknown, making it imperative to closely monitor adrenal size in patients undergoing osilodrostat treatment. As indicated in previous reports, most patients attempt dose reduction or discontinue osilodrostat successfully. Thus, if the adrenal glands shrink, reducing the osilodrostat dose may be feasible without compromising blood cortisol level control. Hence, tracking adrenal size through imaging studies, such as CT and magnetic resonance imaging, in osilodrostat-treated patients becomes essential, and assessing the adrenal pathology in these individuals is equally crucial. In addition to the former hypothesis, there is another hypothesis that the hormones produced by small cell lung cancer change from ACTH to big-ACTH, which has much less potency to increase plasma cortisol levels, due to chemotherapy or progression to undifferentiated carcinomas of small cell lung cancer. However, the CT scan after osilodrostat administration showed that the density of lung cancer did not change and ranged from 30 to 40 HU, which indicated there was no necrotic change in the patient's lung cancer. In addition, the difference in ACTH measurement results between the 2 kits suggested that bioactive ACTH was present in the plasma, and the elevation of serum DOC and 11-DOF indicated that the patient's adrenal glands were stimulated by ACTH. We experienced a case of ectopic ACTH-dependent Cushing syndrome treated with osilodrostat. In this case, a reduction in the osilodrostat dose was needed to maintain serum cortisol levels in the appropriate range, and a concomitant reduction in adrenal gland size was observed. It is important to follow-up not only ACTH and cortisol levels but also adrenal size on imaging studies in patients treated with osilodrostat. Evaluation of the adrenal pathology in these patients is also needed. Learning Points To treat ectopic ACTH-producing Cushing syndrome, osilodrostat is currently available. We found that osilodrostat was able to fully control the blood cortisol levels, and the dose of osilodrostat could be reduced after the patient's blood cortisol level was controlled. In our ectopic Cushing syndrome patient, the enlarged adrenal glands had shrunk in the course of treatment with osilodrostat. Through an unknown mechanism, osilodrostat decreases the size of adrenal glands; this effect enabled us to reduce the dosage of osilodrostat. Acknowledgments We thank Dr Yuki Sakai, Dr Chika Kyo, Dr Tatsuo Ogawa, Dr Masato Kotani, and Dr Tatsuhide Inoue for their extensive literature review and management of this patient. We also appreciate Dr Yuto Yamazaki and Dr Hironobu Sasano for conducting the pathological diagnosis. Contributors All authors made individual contributions to this study. F.S. was involved in the writing, submission, and preparation of tables and images. R.H. was involved in the diagnosis and management of this patient. R.K. was involved in the diagnosis and management of this patient and was responsible for overseeing the study. H.A. was responsible for the original idea and writing the first draft of the manuscript. All authors were involved in writing and reviewing the case report and approving the final draft. Funding No public or commercial funding was received. Disclosures The authors declare no conflicts of interest. Informed Patient Consent for Publication Signed informed consent obtained directly from the patient. Data Availability Statement Original data generated and analyzed during this study are included in this published article. Abbreviations 11-DOF 11-deoxycortisol ACTH adrenocorticotropin CRH corticotropin-releasing hormone CT computed tomography DOC 11-deoxycorticosterone POMC proopiomelanocortin © The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. 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Abstract We investigated the impact of metformin on ACTH secretion and tumorigenesis in pituitary corticotroph tumors. The mouse pituitary tumor AtT20 cell line was treated with varying concentrations of metformin. Cell viability was assessed using the CCK-8 assay, ACTH secretion was measured using an ELISA kit, changes in the cell cycle were analyzed using flow cytometry, and the expression of related proteins was evaluated using western blotting. RNA sequencing was performed on metformin-treated cells. Additionally, an in vivo BALB/c nude xenograft tumor model was established in nude mice, and immunohistochemical staining was conducted for further verification. Following metformin treatment, cell proliferation was inhibited, ACTH secretion decreased, and G1/S phase arrest occurred. Analysis of differentially expressed genes revealed cancer-related pathways, including the MAPK pathway. Western blotting confirmed a decrease in phosphorylated ERK1/2 and phosphorylated JNK. Combining metformin with the ERK1/2 inhibitor Ulixertinib resulted in a stronger inhibitory effect on cell proliferation and POMC (Precursors of ACTH) expression. In vivo studies confirmed that metformin inhibited tumor growth and reduced ACTH secretion. In conclusion, metformin inhibits tumor progression and ACTH secretion, potentially through suppression of the MAPK pathway in AtT20 cell lines. These findings suggest metformin as a potential drug for the treatment of Cushing's disease. Introduction Pituitary neuroendocrine tumors (PitNETs) are common intracranial tumors with an incidence of 1/1000, and pituitary corticotroph tumors (corticotroph PitNETs) account for approximately 15% of all PitNETs. Most corticotroph PitNETs are functional tumors with clinical manifestations of Cushing's disease characterized by central obesity, hypertension, diabetes mellitus, and psychosis (Cui et al., 2021). The increased cortisol due to the overproduction of adrenocorticotropic hormone (ACTH) significantly reduces the overall quality of survival and life expectancy of patients (Sharma et al., 2015; Barbot et al., 2018). Currently, treatment of corticotroph PitNETs mainly relies on surgery resection, pharmacologic therapy or radiotherapy may be considered for patients with residual tumors or those who are unable to undergo surgery. While several agents, such as cabergoline and pasireotide, are clinically approved, the effect is unsatisfactory, and potentially serious side effects exist. Therefore, there is an urgent need to develop novel therapeutic drugs for corticotroph PitNETs. Metformin is a biguanide hypoglycemic agent for the treatment of type 2 diabetes. In addition to its hypoglycemic effect, numerous studies identified the therapeutic role of metformin in the prevention and treatment of various tumors including small cell lung cancer, colorectal cancer, breast cancer, ovarian cancer, and neuroendocrine tumors (Lu et al., 2022; Kamarudin et al., 2019; Wang et al., 2019; Thakur et al., 2019), making metformin a promising adjuvant drug in the therapy of cancers. Besides, it has been reported that metformin improves metabolic and clinical outcomes in patients treated with glucocorticoids. However, to date, limited studies explore the potential anti-cancer effect of metformin in corticotroph PitNETs. Recent studies report the use of metformin for blood glucose and body weight control in patients with Cushing's disease (Ceccato et al., 2015), while the role of metformin on ACTH secretion and tumor growth in corticotroph PitNETs remains to be elucidated. In the current study, we investigated the effect of metformin in corticotroph PitNETs and performed RNA-sequencing to identify the potential mechanisms of metformin. We found that metformin inhibited cell proliferation and ACTH secretion of AtT20 cells in a dose-dependent manner. Besides, metformin induced cell cycle arrest via decreased ERK1/2 phosphorylation and increased P38 phosphorylation. Our results revealed that metformin is a potential drug for corticotroph PitNET therapy. Section snippets Cell culture The ACTH-secreting mouse pituitary tumor cell line AtT-20 was purchased from the American Type Culture Collection (ATCC; Manassas, VA, USA). Cells were cultured in F-12K medium (ATCC; Catalog No. 30-2004), supplemented with 15% fetal bovine serum (FBS; Gibco), and 2.5% horse serum (Gibco) as suggested. AtT20 cells were cultured in a humidified incubator at 37 °C in 5% CO2. Reagents and drugs Metformin and Ulixertinib were purchased from MedChemExpress (MCE), Metformin was dissolved in sterile H2O and prepared as a Results Metformin inhibits cell proliferation and ACTH secretion, and leads to cell cycle arrest in AtT20 cells. We used CCK-8 assay to detect the cell viability of AtT20 cells after treatment with different concentrations of metformin at 24 h, 48 h, and 72 h. The results showed that metformin significantly inhibited the proliferation of AtT20 cells in a dose-dependent manner (Fig. 1A). Similarly, prolonged (6 days) treatment of AtT20 cells with a lower concentration (400 μM) of metformin also inhibited Discussion Metformin, acting by binding to PEN2 and initiating the subsequent AMPK signaling pathway in lysosomes, is the most commonly used oral hypoglycemic agent (Hundal et al., 2000; Ma et al., 2022). Previous reports demonstrated metformin as a potential anti-tumor agent in cancer therapy (Evans et al., 2005). Metformin, either alone or in combination with other drugs, has been shown to reduce cancer risk in a variety of tumors including pituitary neuroendocrine tumors (PitNETs) (Thakur et al., 2019; Conclusion Our study demonstrated that metformin suppressed cell proliferation and decreased ACTH secretion in AtT20 cells via the MAPK pathway. Our results revealed that metformin is a potential anti-tumor drug for the therapy of corticotroph PitNETs, which deserves further study. Funding This study was supported by the National Natural Science Foundation of China (82072804, 82071559). CRediT authorship contribution statement Yingxuan Sun: Conceptualization, Formal analysis, Investigation, Writing – original draft, Writing – review & editing. Jianhua Cheng: Data curation, Formal analysis, Visualization, Writing – original draft, Writing – review & editing. Ding Nie: Formal analysis, Writing – review & editing. Qiuyue Fang: Data curation, Formal analysis, Writing – review & editing. Chuzhong Li: Conceptualization, Supervision, Writing – original draft, Writing – review & editing, Funding acquisition. Yazhuo Zhang: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgement We thank Mr. Hua Gao (Cell Biology Laboratory, Beijing Neurosurgical Institute, China) for support with the techniques. References (30) K. Jin et al. Metformin suppresses growth and adrenocorticotrophic hormone secretion in mouse pituitary corticotroph tumor AtT20 cells Mol. Cell. Endocrinol. (2018) R. Krysiak et al. The effect of metformin on prolactin levels in patients with drug-induced hyperprolactinemia Eur. J. Intern. Med. (2016) X. Liu et al. Combination treatment with bromocriptine and metformin in patients with bromocriptine-resistant prolactinomas: pilot study World neurosurgery (2018) J. Sinnett-Smith et al. Metformin inhibition of mTORC1 activation, DNA synthesis and proliferation in pancreatic cancer cells: dependence on glucose concentration and role of AMPK Biochem. Biophys. Res. Commun. (2013) C.R. Triggle et al. Metformin: is it a drug for all reasons and diseases? Metab., Clin. Exp. (2022) J.C. Wang et al. Metformin inhibits metastatic breast cancer progression and improves chemosensitivity by inducing vessel normalization via PDGF-B downregulation J. Exp. Clin. Cancer Res. : CR (2019) J. An et al. Metformin inhibits proliferation and growth hormone secretion of GH3 pituitary adenoma cells Oncotarget (2017) M. Barbot et al. Diabetes mellitus secondary to Cushing's disease Front. Endocrinol. (2018) F. Ceccato et al. Clinical use of pasireotide for Cushing's disease in adults Therapeut. Clin. Risk Manag. (2015) M. Cejuela et al. Metformin and breast cancer: where are we now? Int. J. Mol. Sci. (2022) From https://www.sciencedirect.com/science/article/abs/pii/S0303720723002915

Here, we report the first adult case of pancreatic yolk sac tumor with ectopic adrenocorticotropic hormone (ACTH) syndrome. The patient was a 27-year-old woman presenting with abdominal distension, Cushingoid features, and hyperpigmentation. Endogenous Cushing’s syndrome was biochemically confirmed. The ACTH level was in the normal range, which raised the suspicion of ACTH precursor-dependent disease. Elevated ACTH precursors were detected, supporting the diagnosis of ectopic ACTH syndrome. Functional imaging followed by tissue sampling revealed a pancreatic yolk sac tumor. The final diagnosis was Cushing’s syndrome due to a yolk sac tumor. The patient received a steroidogenesis inhibitor and subsequent bilateral adrenalectomy for control of hypercortisolism. Her yolk sac tumor was treated with chemotherapy and targeted therapy. Cushing’s syndrome secondary to a yolk sac tumor is extremely rare. This case illustrated the utility of ACTH precursor measurement in confirming an ACTH-related pathology and distinguishing an ectopic from a pituitary source for Cushing’s syndrome. Introduction Ectopic adrenocorticotrophic hormone (ACTH) syndrome, also termed paraneoplastic Cushing’s syndrome, can be caused by the secretion of ACTH and/or ACTH precursors from ectopic tumors. The tumors concerned secrete ACTH precursors, including unprocessed proopiomelanocortin (POMC) and POMC-derived peptides, owing to the altered post-translational processing of POMC (1). These tumors are associated with intense hypercortisolism and various complications, such as hypertension, hyperglycemia, osteoporosis, infection risks, and thrombotic tendencies (2). Distinguishing ectopic from pituitary-dependent Cushing’s syndrome is often challenging. The two conditions are classically distinguished by their variable responses to dynamic endocrine tests, including the high-dose dexamethasone suppression test, the corticotrophin-releasing-factor (CRF) test, and the desmopressin test (3). Pituitary imaging may sometimes provide a diagnosis if a pituitary macroadenoma is identified at this juncture. The gold standard for diagnosing pituitary Cushing’s is a positive inferior petrosal sinus sampling (IPSS) result. The measurement of ACTH precursors is reported to have diagnostic value in this scenario (4). The most common source of ectopic ACTH is intrathoracic tumors, including bronchial carcinoid and small cell lung cancers. Other possible sources include gut neuroendocrine tumors and medullary thyroid cancer. Recognizing the potential causes of ectopic ACTH syndrome is essential as this provides guidance in locating the causative tumor and allows tumor-directed therapies. A yolk sac tumor as a cause of ectopic ACTH syndrome has only been reported in a 2-year-old child but not in adults (5). Here, we present a case of a 27-year-old Chinese woman who had Cushing’s syndrome due to ectopic ACTH precursor production from a pancreatic yolk sac tumor. Case description A 27-year-old Chinese woman, who had unremarkable past health and family history, presented with right upper quadrant abdominal pain and nausea in early 2020. Abdominal ultrasonography was unrevealing. A few months later, she developed Cushingoid features and oligomenorrhea. At presentation, her blood pressure was 160/95 mmHg, body weight was 65.6 kg, and body mass index was 23.2 kg/m2. She had a moon face, hirsutism, proximal myopathy, bruising, thinning of the skin, and acne. She also had hyperpigmentation on the nails and knuckles of both hands (Figure 1). Figure 1 Figure 1. Cushingoid features at presentation include moon face, acne, thin skin, and easy bruising. Hyperpigmentation on the nails and knuckles was also noted. Diagnostic assessments Her 9 am and 9 pm cortisol were both >1,700 nmol/L. Her 24-h urine-free cortisol was beyond the upper measurable limit at >1,500 nmol/L. Her serum cortisol was 759 nmol/L after a 1 mg overnight-dexamethasone suppression test, confirming endogenous Cushing’s syndrome. The morning ACTH was 35 pg/mL (upper limit of normal is 46 pg/mL). After excluding a high dose-hook effect, her blood sample was concomitantly sent for ACTH measurement using two different platforms to eliminate possible interference, which might cause a falsely low ACTH reading. ACTH was 19 pg/mL (upper limit of normal is 46 pg/mL) using an IMMULITE 2000 XPI, Siemens Healthineers, Erlangen, Germany, and 17 pg/mL (reference range: 7–63 pg/mL) using a Cobas e-801, Roche Diagnostics, Indianapolis, IN, United States, therefore verifying the ACTH measurement. In view of this being ACTH-dependent Cushing’s syndrome, a high-dose-dexamethasone suppression test (HDDST) was performed, and her cortisol was not suppressed at 890 nmol/L, with ACTH 42 pg/mL. The serum cortisol day profile showed a mean cortisol level of >1,700 nmol/L (i.e., higher than the upper measurable limit of the assay) and an ACTH of 17 pg/mL. A CRF test using 100 μg of corticorelin showed less than a 50% rise in ACTH and no rise in cortisol levels (Supplementary Table S1). She suffered from multiple complications of hypercortisolism, including thoracic vertebral collapse with back pain, diabetes mellitus (HbA1c 6.7% and fasting glucose 7.6 mmol/L), and hypokalemic hypertension, with a lowest potassium level of 2.3 mmol/L. The rapid onset of intense hypercortisolism and refractory hypokalemia, as well as the responses in the HDDST and CRF tests raised the suspicion of ectopic ACTH syndrome. Tumor markers were measured. Alpha-fetoprotein (AFP) was markedly raised at 33,357 ng/mL (reference range: <9 ng/mL). Beta-human chorionic gonadotropin (beta-hCG) was not elevated. Carcinoembryonic antigen (CEA) was 4.0 ng/mL (reference range: <3 ng/mL) and CA 19–9 was 57 U/mL (reference range: <37 U/mL). The marked hyperpigmentation in the context of normal ACTH levels pointed to the presence of an underlying tumor producing circulating ACTH precursors. Hence, magnetic resonance imaging (MRI) of the pituitary gland was not performed at this juncture. ACTH precursors were measured using a specialized immunoenzymatic assay (IEMA) employing in-house monoclonal antibodies against the ACTH region and the gamma MSH region. Both monoclonal antibodies have to bind to these regions in POMC and pro-ACTH to create a signal. The patient had a level of 4,855 pmol/L (upper limit of normal is 40 pmol/L) (6). This supported Cushing’s syndrome from an ectopic source secondary to an excess in ACTH precursors. Localization studies were arranged to identify the source of ectopic ACTH precursors. Computed tomography (CT) of the thorax did not show any significant intrathoracic lesion but incidentally revealed a pancreatic mass. Dedicated CT of the abdomen confirmed the presence of a 7.9 × 5.6 cm lobulated mass in the pancreatic body; the adrenal glands were unremarkable. 18-FDG and 68Ga-DOTATATE dual-tracer positron-emission tomography-computed tomography (PET-CT) showed that the pancreatic mass was moderately FDG-avid and non-avid for DOTATATE (Supplementary Figure S1). Multiple FDG-avid nodal metastases were also present, including left supraclavicular fossa lymph nodes. Fine needle aspiration of the left supraclavicular fossa lymph node yielded tumor cells featuring occasional conspicuous nucleoli, granular coarse chromatin, irregular nuclei, and a high nuclear-to-cytoplasmic ratio. Mitotic figures were infrequent. On immunostaining, the tumor cells were positive for cytokeratin 7 and negative for cytokeratin 20. Focal expression of CDX-2, chromogranin, and synaptophysin was noted. They were negative for TTF-1, GCDPF, Gata 3, Pax-8, CD56, ACTH, inhibin, and S-100 protein. Further immunostaining was performed in view of highly elevated AFP. The tumor cells expressed AFP, Sall4, and MNF-116. They were negative for c-kit, calretinin, Melan A and SF-1. Placental ALP (PLAP) was weak and equivocal. The features were in keeping with a yolk sac tumor. Therapeutic intervention and outcome The patient had significant hypokalemic hypertension requiring losartan 100 mg daily, spironolactone 100 mg daily, and a potassium supplement of 129 mmol/day. Co-trimoxazole was given for prophylaxis against Pneumocystis jirovecii pneumonia. Metyrapone was started and up-titrated to 1 gram three times per day. However, in view of persistent hypercortisolism, with urinary free cortisol persistently above the upper measurable limit of the assay, bilateral adrenalectomy was performed. The tumor was mainly in the periadrenal soft tissue, with vascular invasion. The tumor formed cords, nests, and ill-defined lumen (Figure 2). The tumor cells were polygonal and contained pale to eosinophilic cytoplasm and pleomorphic nuclei, some with large nucleoli. Mitosis was present while tumor necrosis was not obvious. The stroma was composed of vascular fibrous tissue, with minimal inflammatory reaction. Immunohistochemical study showed that the tumor was positive for cytokeratin 7, MNF-116, AFP, and glypican-3, and also positive for Sall4 and HNF1β. The tumor cells were negative for cytokeratin 20, PLAP, CD30, negative for neuroendocrine markers including S100 protein, synaptophysin, chromogranin, and also negative for Melan-A, inhibin, and ACTH. Histochemical study for Periodic acid–Schiff–diastase (PAS/D) showed no cytoplasmic zymogen granules like those of acinar cell tumor. The features were compatible with yolk sac tumor. She was put on glucocorticoid and mineralocorticoid replacements post-operatively. Figure 2 Figure 2. Histology and immunohistochemical staining pattern of tumor specimen. (A) HE stain x 40 showing tumor cells in the soft tissue and peritoneum. (B) HE × 400 showing that the tumor forms cords, nests, and ill-formed lumen in the vascular stroma. The tumor cells are polygonal with pale cytoplasm and pleomorphic nuclei. (C) PAS/D stain showing no cytoplasmic zymogen granules. (D) Tumor is diffusely positive for cytokeratin 7. (E) Tumor is positive for AFP. (F) Tumor is positive for glypican-3. (G) Tumor is diffusely positive for HNF1β. (H) Tumor is diffusely positive for SALL4. Regarding her oncological management, she received multiple lines of chemotherapy, but the response was poor. Due to limited access to the ACTH precursor assay, serial measurement was unavailable. Treatment response was monitored by repeated imaging and monitoring of AFP. Figure 3 shows a timeline indicating the key events of the disease, showing the trends of the AFP and cortisol levels. Apart from (i) bleomycin, etoposide, and platinum, she was sequentially treated with (ii) etoposide, ifosfamide with cisplatin, and (iii) palliative gemcitabine with oxaliplatin. Next-generation sequencing showed a BRAF V600E mutation, for which (iv) dabrafenib and trametinib were given. Unfortunately, the disease progressed, and the patient succumbed approximately one year after the disease was diagnosed. Figure 3 Figure 3. Timeline with serial cortisol and alpha-fetoprotein levels from diagnosis to patient death. Discussion This case demonstrates the diagnostic value of ACTH precursor measurement in the diagnosis of ectopic Cushing’s syndrome. ACTH precursors are raised in all ectopic tumors responsible for Cushing’s syndrome and could be useful in distinguishing ectopic from pituitary Cushing’s syndrome (4). Moreover, Cushing’s syndrome due to a yolk sac tumor has been reported only once in a pediatric case, and this is the first adult case reported in the literature (5). POMC is sequentially cleaved in the anterior pituitary into pro-ACTH and then into ACTH, which is released into the circulation and binds to ACTH receptors in the adrenal cortex, leading to glucocorticoid synthesis (5, 7). Due to incomplete processing, ACTH precursors are found in normal subjects at a concentration of 5–40 pmol/L (6). Pituitary tumors are traditionally well-differentiated and can also relatively efficiently process ACTH precursors. However, this processing is less efficient in ectopic tumors that cause Cushing’s syndrome (8). Some less differentiated pituitary macroadenomas can secrete ACTH precursors into the circulation; however, these tumors are diagnosed by imaging and so do not, in general, cause problems with differential diagnosis (9). Measurement of ACTH precursors by immunoradiometric assay (IRMA) was first described by Crosby et al. (10). The assay utilized monoclonal antibodies specific for ACTH and the other binding gamma-MSH. The assay only detects peptides expressing both epitopes and therefore measures POMC and pro-ACTH. The assay does not cross-react with other POMC-derived peptides such as beta-lipotropin, ACTH, and N-POMC. Oliver et al. demonstrated that, compared to the pituitary adenomas in Cushing’s disease, all ectopic tumors responsible for Cushing’s syndrome in their study produce excessive POMC and pro-ACTH (4). The excessive production of ACTH precursors may reflect neoplasm-induced modification and amplification of POMC production. It is suggested that POMC binds to and activates the ACTH receptor because it contains the ACTH amino-acid sequence, or it is cleaved to ACTH in the adrenal glands to cause hypercortisolism (5) (Figure 4). Moreover, cleavage of POMC may produce peptides that exert mitogenic actions on adrenal cells and lead to adrenocortical growth. Outside the adrenal tissue, excessive ACTH precursors in Cushing’s syndrome caused by ectopic tumors can lead to marked hyperpigmentation. Both hypercortisolism and hyperpigmentation were observed in the reported case. Figure 4 Figure 4. Postulated pathological mechanism of ectopic ACTH precursors. In patients with ACTH-dependent Cushing’s syndrome, ectopic tumors should be distinguished from pituitary tumors. The HDDST, at a cut-off of 50% cortisol suppression, gives a sensitivity of 81% and a specificity of 67% for pituitary dependent Cushing’s syndrome (11). The CRF test provides 82% sensitivity and 75% specificity for pituitary disease (8). IPSS is the gold standard in distinguishing pituitary from ectopic tumors in Cushing’s syndrome. Utilization of CRF-stimulated IPSS provides 93% sensitivity and 100% specificity for pituitary disease. It also allows correct lateralization in 78% of patients with pituitary tumors. However, it is only available in specialized centers. In a retrospective cohort, the ACTH precursor level distinguished well between Cushing’s disease and ectopic ACTH syndrome (4). With a cut-off of 100 pmol/L, the test achieved 100% sensitivity and specificity for ectopic ACTH syndrome. More recently, this assay has been used to diagnose patients with occult ectopic ACTH syndrome, with ACTH precursors above 36 pmol/L (8). Unfortunately, the immunoassay for ACTH precursor measurement utilizes in-house monoclonal antibodies, which are not widely available. Cross-reactivity of POMC in commercially available ACTH assays ranges from 1.6% to 4.7% (12). In cases of ectopic tumors causing Cushing’s syndrome with markedly raised ACTH-precursors and intense hypercortisolism, the cross-reactivity would give significantly high ‘ACTH’ measurements to suggest an ACTH-related pathology. The degree of cross-reactivity, which is variable, should ideally be provided by the assay manufacturer as it affects result interpretation. Lower levels of ACTH precursor production might not be detected, especially by assays with low precursor cross-reactivity. Clinical vigilance is crucial in reaching the correct diagnosis. In patients with marked hypercortisolism and a normal ACTH concentration, like in this case, the measurement of ACTH precursors would allow the accurate diagnosis of Cushing’s syndrome caused by ACTH precursors. Ectopic tumors causing Cushing’s syndrome are associated with more intense hypercortisolism than Cushing’s disease (11). However, due to variable cross-reactivity, commercial ACTH assays might not accurately detect the excessive ACTH precursors responsible for the clinical syndrome. For this reason, ACTH measurements in these two conditions can significantly overlap and may not differentiate between ectopic and pituitary diseases (4). On the other hand, the more specific POMC assay described in 1996, which does not cross-react with pro-ACTH, has a low sensitivity of 80% for ectopic Cushing’s syndrome and is not now available (13). Hence, the ACTH precursor assay used in this reported case, which detects POMC and pro-ACTH, appears to provide the best diagnostic accuracy from the available literature. Serial measurement of ACTH precursors may play a role in monitoring the treatment response in an ACTH precursor secreting tumor. In the case of ectopic ACTH secretion, the corticotropic axis is slowed down and ACTH is almost exclusively of paraneoplastic origin. Immunotherapy is known to alter the functioning of the hypothalamic–pituitary corticotropic axis; however, its effect on ectopic secretions is not known. More data is required before the role of ACTH precursor measurement for disease monitoring in these scenarios can be ascertained. The incidence of endogenous Cushing’s syndrome is reported to be 2 to 4 per million people per year (14). Ectopic sources of Cushing’s syndrome are responsible for 9 to 18% of these cases. Typical sources of these ectopic tumors include bronchial carcinoid tumors, small-cell lung cancer, and gut neuroendocrine tumors. Notably, germ cell tumors, including teratomas, ovarian epithelial tumors, and ovarian endometrial tumors, are also possible ectopic sources of Cushing’s syndrome. The histological diagnosis of germ cell tumor in a non-genital site is challenging, especially for the poorly differentiated, or with somatic differentiation. Immunostaining, chromosomal, or genetic study are very important in confirming the diagnosis. AFP elevation in our case limited the differential diagnoses to germ cell tumors/yolk sac tumors, hepatocellular carcinoma, and rare pancreatic tumors. The specimen was biopsied from the retroperitoneum, and the morphology was a dominant trabecular pattern or a hepatoid pattern. It showed diffuse positive immunostaining for cytokeratin, AFP, and glypican-3. It was also diffusely and strongly positive for HNF1β and SALL4, supporting the diagnosis of yolk sac tumor. Both HNF1β and SALL4, being related with the expression of genes associated with stem cells or progenitor cells, are used as sensitive and specific markers for germ cell tumors/yolk sac tumors (15, 16). Staining related to pancreatic acinar cell carcinoma and neuroendocrine tumor were performed. PAS/D staining showed a lack of zymogen granules. A lack of nuclear β-catenin positivity was shown. Staining for neuroendocrine markers, including chromogranin and synaptophysin, was negative. Bcl-10 and trypsin were not available in the local setting. Cushing’s syndrome due to a yolk sac tumor was reported only once, in a 2-year-old child (5). The abdominal yolk sac tumor was resistant to cisplatin, with rapid disease progression, and the patient succumbed 1.5 years after initial presentation. Yolk sac tumor in the pancreas is also rare, with only 4 cases reported so far. The first case was reported in a 57-year-old woman with an incidentally detected abdominal mass (17). The tumor stained positive for AFP, PLAP, and CEA. The second case was a 70-year-old asymptomatic woman with histology showing a group of tumor cells with features of a yolk sac tumor, and another group showing features of pancreatic ductal adenocarcinoma with mucin production, suggesting a yolk sac tumor derived from pancreatic ductal adenocarcinoma (18). The tumor showed partial positivity for AFP, Sall4, glypican-3, and cytokeratin 7, as found in our case, while MNF-116 and PLAP staining results were not described. The third was in a 33-year-old man with a solitary pancreatic head mass with obstructive jaundice (19). The patient had undergone Whipple’s procedure followed by cisplatin-based chemotherapy, resulting in at least 5 years of disease remission. The latest reported case was in a 32-year-old man presenting with abdominal pain (20). Notably, initial imaging showed diffuse enlargement of the pancreas and increased FDG uptake without a distinct mass. Reassessment imaging 11 months later showed a 13 cm pancreatic mass. The initial imaging findings suggested initial intraductal growth of the tumor, as reported in some subtypes of pancreatic carcinoma. None of the reported cases of adult pancreatic yolk sac tumors were associated with abnormal hormone secretion. We reported the first adult case of pancreatic yolk sac tumor with ectopic ACTH syndrome. The case represents an overlap of two rarities. It demonstrates that pancreatic yolk sac tumor is a possible cause of ectopic ACTH syndrome. Conclusion ACTH precursor measurement helps to distinguish ectopic ACTH syndrome from Cushing’s disease. The test has superior diagnostic performance and is less invasive than IPSS. Nonetheless, the limited availability of the assay may restrict its broader use in patient management. We describe the first adult case of pancreatic yolk sac tumor with ACTH precursor secretion resulting in Cushing’s syndrome. This adds to the list of origins of ectopic ACTH syndrome in adults. Data availability statement The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author. Ethics statement Written informed consent was obtained from the individual to publish any potentially identifiable images or data in this article. Author contributions JC wrote the manuscript. JC, CW, WC, AW, KW, and PT researched the data. WC, AL, EL, YW, KT, KL, and CL critically reviewed and edited the manuscript. DL initiated and conceptualized this case report and is the guarantor of this work. All authors contributed to the article and approved the submitted version. Funding The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article. Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Publisher’s note All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Supplementary material The Supplementary material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmed.2023.1246796/full#supplementary-material References 1. Stewar, PM, Gibson, S, Crosby, SR, Pennt, R, Holder, R, Ferry, D, et al. ACTH precursors characterize the ectopic ACTH syndrome. Clin Endocrinol. (1994) 40:199–204. doi: 10.1111/j.1365-2265.1994.tb02468.x PubMed Abstract | CrossRef Full Text | Google Scholar 2. Young, J, Haissaguerre, M, Viera-Pinto, O, Chabre, O, Baudin, E, and Tabarin, A. 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(2022) 14:e26007. doi: 10.7759/cureus.26007 PubMed Abstract | CrossRef Full Text | Google Scholar 20. Sui, H, Zhu, Z, Li, Z, and Luo, Y. Primary pancreatic yolk sac tumor presenting as diffusely enlarged pancreas in initial 18F-FDG PET/CT. Clin Nucl Med. (2020) 45:483–6. doi: 10.1097/RLU.0000000000003038 PubMed Abstract | CrossRef Full Text | Google Scholar Keywords: Cushing’s syndrome, ectopic ACTH syndrome, yolk sac tumor, pancreatic tumor, ACTH precursor Citation: Chang JYC, Woo CSL, Chow WS, White A, Wong KC, Tsui P, Lee ACH, Leung EKH, Woo YC, Tan KCB, Lam KSL, Lee CH and Lui DTW (2023) Cushing’s syndrome caused by ACTH precursors secreted from a pancreatic yolk sac tumor in an adult—a case report and literature review. Front. Med. 10:1246796. doi: 10.3389/fmed.2023.1246796 Received: 18 July 2023; Accepted: 20 November 2023; Published: 05 December 2023. Edited by: Alessandro Vanoli, University of Pavia, Italy Reviewed by: Petar Brlek, St. Catherine Specialty Hospital, Croatia Wafa Alaya, Hospital University Tahar Sfar, Tunisia Copyright © 2023 Chang, Woo, Chow, White, Wong, Tsui, Lee, Leung, Woo, Tan, Lam, Lee and Lui. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. *Correspondence: David Tak Wai Lui, dtwlui@hku.hk Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. From https://www.frontiersin.org/articles/10.3389/fmed.2023.1246796/full

In this study, we will investigate the possible side effects of psoriasis patients using long-term topical corticosteroids (TCS) such as adrenal insufficiency, Cushing’s Syndrome (CS) and osteoporosis and determine how these side effects develop. Forty-nine patients were included in the study. The patients were divided into two groups based on the potency of the topical steroid they took and the patients’ ACTH, cortisol and bone densitometer values were evaluated. There was no significant difference between the two groups regarding the development of surrenal insufficiency, CS and osteoporosis. One patient in group 1 and 4 patients in group 2 were evaluated as iatrogenic CS. ACTH stimulation tests of these patients in group 2 showed consistent results with adrenal insufficiency, while no adrenal insufficiency was detected in the patient in Group 1. Patients who used more than 50g of superpotent topical steroids per week compared to patients who used 50g of superpotent topical steroids per week. It was identified that patients who used more than 50g of superpotent topical steroids had significantly lower cortisol levels, with a negatively significant correlation between cortisol level and the amount of topical steroid use ( < .01).Osteoporosis was detected in 3 patients in group 1 and 8 patients in Group 2. Because of the low number of patients between two groups, statistical analysis could not be performed to determine the risk factors. Our study is the first study that we know of that investigated these three side effects. We have shown that the development of CS, adrenal insufficiency and osteoporosis in patients who use topical steroids for a long time depends on the weekly TCS dosage and the risk increases when it exceeds the threshold of 50 grams per week. therefore, our recommendation would be to avoid long-term use of superpotent steroids and to choose from the medium-potent group if it is to be used. ABOUT THE CONTRIBUTORS Betul Erdem Department of Dermatology, Van Training and Research Hospital, Van, Turkey. Muzeyyen Gonul Department of Dermatology, Ministry of Health, Ankara Etlik City Hospital, Ankara, Turkey. Ilknur Ozturk Unsal Department of Endocrine and Metabolic Disease, Ministry of Health, Ankara Etlik City Hospital, Ankara, Turkey. Seyda Ozdemir Sahingoz Department of Biochemistry, Ministry of Health, Ankara Etlik City Hospital, Ankara, Turkey. From https://www.physiciansweekly.com/evaluation-of-psoriasis-patients-with-long-term-topical-corticosteroids-for-their-risk-of-developing-adrenal-insufficiency-cushings-syndrome-and-osteoporosis/

The following is a summary of “Diurnal Range and Intra-patient Variability of ACTH Is Restored With Remission in Cushing’s Disease,” published in the November 2023 issue of Endocrinology by Alvarez, et al. Distinguishing Cushing’s disease (CD) remission from other conditions using single adrenocorticotropic hormone (ACTH) measurements poses challenges. For a study, researchers sought to analyze changes in ACTH levels before and after transsphenoidal surgery (TSS) to identify trends confirming remission and establish ACTH cutoffs for targeted clinical trials. A retrospective analysis involved 253 CD patients undergoing TSS at a referral center from 2005 to 2019. Remission outcomes were assessed based on postoperative ACTH levels. Among 253 patients, 223 achieved remission post-TSS. The remission group exhibited higher ACTH variability at morning (AM) (P = .02) and evening (PM) (P < .001) time points compared to the nonremission group. Nonremission cases had a significantly narrower diurnal ACTH range (P < .0001). A ≥50% decrease in plasma ACTH from mean preoperative levels, especially in PM values, predicted remission. Absolute plasma ACTH concentration and the ratio of preoperative to postoperative values were associated with nonremission (adj P < .001 and .001, respectively). ACTH variability suppression was observed in CD, with remission linked to restored variability. A ≥50% decrease in plasma ACTH may predict CD remission post-TSS. The insights can guide clinicians in developing rational outcome measures for interventions targeting CD adenomas. Source: academic.oup.com/jcem/article-abstract/108/11/2812/7187942?redirectedFrom=fulltext

Abstract Paraneoplastic syndromes are rare and diverse conditions caused by either an abnormal chemical signaling molecule produced by tumor cells or a body’s immune response against the tumor itself. These syndromes can manifest in a variable, multisystemic and often nonspecific manner posing a diagnostic challenge. We report the case of an 81-year-old woman who exhibited severe hypokalemia, metabolic alkalosis, and worsening hyperglycemia. The investigation was consistent with adrenocorticotropin (ACTH)-dependent Cushing’s syndrome and, eventually, the patient was diagnosed with stage IV primary small-cell lung cancer (SCLC). SCLC is known to be associated with paraneoplastic syndromes, including Cushing’s syndrome caused by ectopic adrenocorticotropin (ACTH) secretion. Despite being associated with very poor outcomes, managing these syndromes can be challenging and may hold prognostic significance. Introduction Adrenocorticotropin (ACTH)-dependent Cushing’s syndrome (CS) is caused by excessive ACTH production by corticotroph (Cushing’s disease (CD)) or nonpituitary (ectopic) tumors, leading to excessive cortisol production. Ectopic ACTH syndrome (EAS) is a rare condition, accounting for 10 to 20% of all cases of ACTH-dependent CS and 5 to 10% of all types of CS [1]. The normal glucocorticoid-induced suppression of ACTH is reduced in ACTH-dependent CS, especially with ectopic ACTH production. Studies show that a wide variety of neoplasms, usually carcinomas rather than sarcomas or lymphomas, have been associated with EAS. Most cases are caused by neuroendocrine tumors of the lung, pancreas, or thymus, in which the hypercortisolism state is not apparent clinically, resulting, all too often, in delayed diagnosis [2,3]. Current diagnostic tests for EAS aim to confirm high cortisol levels, the absence of a cortisol circadian rhythm, as well as the reduced response to negative feedback from glucocorticoid administration, and imaging to identify the site of ACTH production. Prompt diagnosis and management are crucial in EAS, highlighting the importance of physician awareness and early recognition of this syndrome. Treatment options depend on the underlying tumor. Surgical removal is often the primary approach, followed by radiation therapy or chemotherapy. Additionally, medications to control cortisol levels may be necessary to manage the various comorbid conditions associated with CS, such as cardiovascular disease, diabetes, electrolyte imbalances, infections and thrombotic risk [4,5]. Case Presentation We report the case of an 81-year-old woman with a fully active performance status (ECOG 0) and a medical history of diabetes, hypertension, dyslipidemia, and depressive disorder. She was admitted to an internal medicine ward due to an acute hydroelectrolytic disorder, including metabolic alkalosis, severe hypokalemia (2 mmol/L), hypochloremia (85 mmol/L), hypocalcemia (0.95 mmol/L), hypophosphatemia (1.4 mg/dL), hypomagnesemia (0.9 mg/dL), and hyperlactatemia (5.8 mmol/L), after she reportedly self-medicated herself with higher doses of metformin (four to five pills a day) due to high blood glucose levels. The patient presented with asthenia, nausea, vomiting, and diarrhea for three days and reported uncontrolled blood glucose levels for the last eight days. The physical examination was unremarkable, without any altered mental status or signs of infection. Arterial blood gas samples showed metabolic alkalemia (pH 7.59) and hyperlactatemia, associated with severe hypokalemia, normal bicarbonate (27 mmol/L), and mildly elevated glycemia and ketonemia (232 mg/dL and 1.7 mmol/L, respectively). Lab tests confirmed the serum potassium levels as well as the other aforementioned electrolyte disturbances. Kidney function and hepatic enzymes were normal. Considering the possible relationship between the electrolyte disorder and the gastrointestinal presentation, the patient was given intravenous (IV) fluids and received potassium and magnesium replacement therapy. Despite receiving 200 milliequivalents (mEq) of IV potassium chloride and 4 grams of magnesium sulfate, in the first 48 hours, the ion deficits persisted. Given the persistent electrolyte derangement, the patient was admitted to the Internal Medicine ward for etiological investigation and monitoring of ionic correction. The initial period was remarkable for refractory hypokalemia and uncontrolled diabetes under respective therapeutic measures, including 80 to 130 mEq of IV potassium chloride and progressive titration of spironolactone to 200 mg a day. Laboratory investigation revealed high parathormone levels (PTHi 167 pg/mL; reference range: 10-65 pg/mL), vitamin D deficiency (3.3 ng/mL; reference range >20 ng/mL) and apparent ACTH-dependent hypercortisolism (serum cortisol 80.20 ug/dL; ACTH 445 pg/mL), as well as high urinary potassium and glucose concentrations (190 mEq/24 h and 21161 mg/24 h). A dexamethasone suppression test was performed twice (standard low and high dose) without any changes in cortisol levels, leading to the suspicion of a CS caused by abnormally high ACTH production. Cranioencephalic computed tomography (CT) and magnetic resonance imaging (MRI) were performed, excluding the presence of pituitary anomalies. A follow-up whole-body CT scan was performed, revealing a suspicious pulmonary mass in the left lower lobe, associated with ipsilateral hilar lymphadenopathy and hepatic and adrenal gland lesions suggestive of secondary involvement. An endobronchial ultrasound bronchoscopy and biopsy were performed, documenting anatomopathological findings of small-cell lung carcinoma with a Ki67 expression of 100% (Figures 1-3). Figure 1: Pulmonary mass (SCLC) in the left lower lobe with ipsilateral hilar lymphadenopathy and pleural effusion. SCLC: small-cell lung cancer. Figure 2: Secondary involvement of the liver with hypodense multilobar hepatic lesions (arterial phase). Figure 3: Bilateral suprarenal lesions suggestive of secondary involvement. The patient was referred to oncology, and chemotherapy was deferred, considering the infectious risk associated with hypercortisolism. The patient started metyrapone 500 mg every eight hours, resulting in a reduction in cortisol levels and control of hypokalemia. Later on, a fluorodeoxyglucose-positron emission tomography (FDG-PET) scan was performed, confirming disseminated disease with additional bone involvement. Unfortunately, despite endocrinological stabilization, the patient's condition worsened, and she ended up dying one month after the diagnosis. Discussion When this patient was admitted, it was assumed that the metabolic alkalosis and various electrolyte disturbances were related to the gastrointestinal presentation and hyperlactatemia secondary to metformin overdose. However, the unusual persistence and refractory hypokalaemia raised some concerns that an alternative etiology might be involved and incited subsequent testing. The high cortisol levels were unexpected given the subclinical presentation, which seems to be more frequent in cases of EAS. In fact, because of this, the true incidence of EAS is unknown and probably underdiagnosed since patients often have subclinical presentations and do not exhibit catabolic features. Since the patient wasn’t on any steroid medication, the association between the high cortisol and ACTH levels, non-responsive to the dexamethasone suppression test, along with the absence of a pituitary lesion, raised suspicion of a probable EAS, which was later confirmed by the body CT scan and endobronchial ultrasound (EBUS). EAS is a rare disease with a poor prognosis. It reportedly occurs in 3.2 to 6% of neuroendocrine neoplasms, and the tumor often originates in the lung, thyroid, stomach, and pancreas. Locoregional and/or distant metastasis can be seen at the time of diagnosis in 15% of typical carcinoids and about half of atypical carcinoids with visible primaries [6,7]. The presence of a typical CS presentation, with or without electrolyte abnormalities, should raise suspicion and serum levels of both ACTH and cortisol should be assessed to determine if they are elevated and to distinguish between an ACTH-dependent (pituitary or nonpituitary ACTH-secreting tumor) and an independent mechanism (e.g., from an adrenal source). The diagnosis of CS is established when at least two different first-line tests are unequivocally abnormal and cannot be explained by any other conditions that cause physiologic hypercortisolism. Additional evaluation is performed to rule out a pituitary origin (with brain MRI) and to assess for a possible ectopic ACTH-secreting tumor. In the aforementioned case, the production of ACTH was caused by primary neuroendocrine SCLC. The recommended approach to EAS involves the initial normalization of serum cortisol levels and the treatment of related comorbidities before performing a complete diagnostic evaluation and addressing the underlying cause [5-7]. This approach seems to improve survival and prevent complications such as sepsis following a combined steroid-induced immunosuppression and chemotherapy-induced agranulocytosis [6,7]. Direct therapies vary according to the tumor, but surgery is usually the first line of treatment (transsphenoidal surgery in cases of CD or tumor resection in cases of non-metastatic EAS). However, our patient presented with stage IV SCLC with EAS, in which chemotherapy remains the first-line treatment. SCLC patients with EAS have a poorer prognosis than those without EAS, with a life expectancy of only three to six months. This makes early diagnosis more important [2,7], as controlling the high cortisol levels and then administering systemic chemotherapy may achieve longer survival [8]. Apart from systemic chemotherapy, ketoconazole (widely accepted but highly toxic), metyrapone, mitotane (adrenocortical suppressant drug with significant side effects), and mifepristone (glucocorticoid antagonist, mainly used for the treatment of hyperglycemia in CS) can be used to reduce circulating glucocorticoids. Moreover, thromboprophylaxis and Pneumocystis jirovecii pneumonia prophylaxis should be started. Because ketoconazole may increase the risk of chemotherapy toxicity by inhibiting cytochrome P450 3A4, metyrapone has been reported to be a better choice [5,7]. Nonetheless, administration of chemotherapy in the setting of a hypercortisolism-induced immunosuppressive state, cancerous background and metabolic disorders featuring electrolyte disturbance and hyperglycemia, aggravate the condition and can be life-threatening. Thus, a palliative approach can sometimes be reasonable. Conclusions The diagnosis of CS is a three-step process that includes its suspicion based on the patient's laboratory and semiologic findings, the documentation of hypercortisolism, and the identification of its cause, which can be either ACTH-dependent or independent. The ectopic secretion of ACTH (EAS) by nonpituitary tumors is a relatively rare cause of CS and often presents as paraneoplastic syndromes, adding therapeutic and prognostic concerns. This case, in particular, highlights the importance of seeking alternative explanations for common electrolyte disturbances, particularly when they don't resolve promptly. Clinicians should be aware of EAS and its frequent subclinical presentation in order to initiate the diagnostic workup as soon as suspicion arises. References Hayes AR, Grossman AB: The ectopic adrenocorticotropic hormone syndrome: rarely easy, always challenging. Endocrinol Metab Clin North Am. 2018, 47:409-25. 10.1016/j.ecl.2018.01.005 Ilias I, Torpy DJ, Pacak K, Mullen N, Wesley RA, Nieman LK: Cushing's syndrome due to ectopic corticotropin secretion: twenty years' experience at the National Institutes of Health. J Clin Endocrinol Metab. 2005, 90:4955-62. 10.1210/jc.2004-2527 Lacroix A, Feelders RA, Stratakis CA, Nieman LK: Cushing’s syndrome. Lancet. 2015, 29:913-27. 10.1016/S0140-6736(14)61375-1 Nieman LK: Molecular derangements and the diagnosis of ACTH-dependent Cushing's syndrome. Endocr Rev. 2022, 43:852-77. 10.1210/endrev/bnab046 Nieman LK, Biller BM, Findling JW, Murad MH, Newell-Price J, Savage MO, Tabarin A: Treatment of Cushing's syndrome: an endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2015, 100:2807-31. 10.1210/jc.2015-1818 Bostan H, Duger H, Akhanli P, et al.: Cushing's syndrome due to adrenocorticotropic hormone-secreting metastatic neuroendocrine tumor of unknown primary origin: a case report and literature review. Hormones (Athens). 2022, 21:147-54. 10.1007/s42000-021-00316-z Richa CG, Saad KJ, Halabi GH, Gharios EM, Nasr FL, Merheb MT: Case-series of paraneoplastic Cushing syndrome in small-cell lung cancer. Endocrinol Diabetes Metab Case Rep. 2018, 2018:4. 10.1530/EDM-18-0004 Zhang HY, Zhao J: Ectopic Cushing syndrome in small cell lung cancer: a case report and literature review. Thorac Cancer. 2017, 8:114-7. 10.1111/1759-7714.12403 From https://www.cureus.com/articles/198133-adrenocorticotropin-dependent-ectopic-cushings-syndrome-a-case-report#!/

Background: Cushing’s disease (CD) poses significant challenges in its treatment due to the lack of reliable biomarkers for predicting tumor localization or postoperative clinical outcomes. Sphingosine-1-phosphate (S1P) has been shown to increase cortisol biosynthesis and is regulated by adrenocorticotropic hormone (ACTH). Methods: We employed bilateral inferior petrosal sinus sampling (BIPSS), which is considered the gold standard for diagnosing pituitary sources of CD, to obtain blood samples and explore the clinical predictive value of the S1P concentration ratio in determining tumor laterality and postoperative remission. We evaluated 50 samples from 25 patients who underwent BIPSS to measure S1P levels in the inferior petrosal sinuses bilaterally. Results: Serum S1P levels in patients with CD were significantly higher on the adenoma side of the inferior petrosal sinus than on the nonadenoma side (397.7 ± 15.4 vs. 261.9 ± 14.88; P < 0.05). The accuracy of diagnosing tumor laterality with the interpetrosal S1P and ACTH ratios and the combination of the two was 64%, 56% and 73%, respectively. The receiver operating characteristic curve analysis revealed that the combination of interpetrosal S1P and ACTH ratios, as a predictor of tumor laterality, exhibited a sensitivity of 81.82% and a specificity of 75%, with an area under the curve value of 84.09%. Moreover, we observed that a high interpetrosal S1P ratio was associated with nonremission after surgery. Correlation analyses demonstrated that the interpetrosal S1P ratio was associated with preoperative follicle-stimulating hormone (FSH), luteinizing hormone (LH), and postoperative ACTH 8 am levels (P < 0.05). Conclusion: Our study demonstrated a significant association between the interpetrosal S1P ratio and tumor laterality, as well as postoperative remission in CD, suggesting that the interpetrosal S1P ratio could serve as a valuable biomarker in clinical practice. 1 Introduction Cushing’s disease (CD), also known as adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma, arises from the pituitary corticotroph cells and induces endogenous hypercortisolism by stimulating the adrenal glands to produce excessive amount of cortisol (1). Patients with CD typically exhibit symptoms of hypercortisolism, such as hypertension, diabetes, purplish skin striae, mental disturbances, hyposexuality, hirsutism, menstrual disorders, acne, fatigue, obesity, and osteoporosis (1). The overall mortality of patients with CD is twice that of the general population, and if left untreated, hypercortisolism resulting from CD increases this rate to approximately four times the expected value (2–4). Transsphenoidal surgery continues to be the primary treatment for CD (5). However, previous studies reported variable remission rates, ranging from 45% to 95% (6–8). Long-term follow-up data have revealed recurrence in 3–66% of patients who had initially achieved complete remission (9, 10). The rate of surgical remission in CD can be influenced by various factors, including the size and location of the tumor, expertise of the neurosurgeon, and criteria used for assessing remission (11). Preoperative clinical variables, such as age, gender, disease duration, and severity of clinical signs and symptoms, cannot reliably identify patients at a higher risk of nonremission (12, 13). Therefore, predicting postsurgical remission in CD remains a challenging goal. Accumulating evidence has shown that sphingosine-1-phosphate (S1P), an intracellular pleiotropic bioactive sphingolipid metabolite synthesized by sphingosine kinase 1 (SPHK1), plays a pivotal role in diverse endocrine disorders (14–16). Overexpression of SPHK1 promotes the progression of multiple neuroendocrine tumors (17, 18). ACTH can rapidly activate sphingolipid metabolism, causing an increase in S1P secretion in the adrenal cortex (19). Furthermore, the activation of S1P signaling in H295R cells, a human adrenocortical tumor cell line, has been suggested to induce increased transcription of hormone-sensitive lipase and steroidogenic acute regulatory protein, ultimately elevating cortisol production (20). Recently, surgical removal of ACTH-secreting adenoma has been reported to cause a decline in sphingomyelin levels (21). However, whether they have a similar role in the pituitary gland remains to be investigated. Bilateral inferior petrosal sinus sampling (BIPSS) is a highly effective procedure for diagnosing pituitary sources of ACTH in CD (22, 23). Contemporaneous differences in ACTH concentration during venous sampling between the two sides of the adenoma can predict the location of the adenoma within the pituitary (on the side of the gland with a microadenoma) and may guide surgical treatment in cases with inconclusive magnetic resonance imaging findings. Previous studies demonstrated that an ACTH gradient of ≥1.4 between the inferior petrosal sinuses can indicate microadenoma lateralization in patients with CD (24–26). However, the correct lateralization only occurs in 57–68% of all cases (27–29). Therefore, we analyzed the clinical behavior of a well-characterized cohort of patients with CD who underwent BIPSS before surgery. We measured the difference in the concentration of S1P in bilateral petrosal sinus blood samples and explored the clinical predictive value of the S1P concentration ratio in determining tumor laterality and postoperative remission. 2 Materials and methods 2.1 Patients and study design This study was conducted at a tertiary center, involving a cohort of 25 patients diagnosed with CD who had undergone BIPSS and surgery, with a minimum follow-up duration of 2 years. Comprehensive chart reviews were conducted to collect data on demographics, clinical characteristics, pituitary imaging findings, tumor pathology, and biochemical tests. The criteria used for diagnosing CD encompassed the presence of characteristic signs and symptoms of hypercortisolism, along with biochemical evaluation of two urinary free cortisol measurements exceeding the normal range for the respective assay, serum cortisol level >1.8 μg/dL (50 nmol/L) after an overnight 1-mg dexamethasone suppression test, and two late-night salivary cortisol measurements exceeding the normal range for the respective assay (30). A diagnosis of Cushing’s syndrome was established if the patient had positive test results for at least two of the three aforementioned tests. Adrenal insufficiency was diagnosed if patients exhibited symptoms or signs of adrenal insufficiency or if serum cortisol levels were ≤3 μg/dL, even in the absence of clinical signs or symptoms. Remission was defined as normalization of the levels of 24-h urinary free cortisol, late-night salivary cortisol, and overnight 1-mg dexamethasone suppression test in patients without concurrent central adrenal insufficiency after surgery (31). 2.2 Patients and tissue/serum samples Surgical specimens of CD-affected tissues were collected from Xiangya Hospital, Central South University. Three normal pituitary tissues were obtained from cadaveric organ donors without any history of endocrine disease (Central South University). A total of 25 CD tissue samples were obtained for immunohistochemistry analysis. This study was conducted in compliance with the Helsinki Declaration and was ethically approved by the Xiangya Hospital Ethics Committee, Xiangya Hospital (Changsha, China). Tumor samples and corresponding clinical materials were obtained with written consent from all patients. 2.3 BIPSS After obtaining informed consent, BIPSS was performed using standard techniques described in previous studies (32, 33). Briefly, the patient’s head was immobilized to ensure midline positioning and prevent any potential bias towards asymmetric pituitary drainage by the petrosal sinuses. After placing peripheral catheters and cannulating both inferior petrosal sinuses, blood samples were collected at baseline and at 3, 5, 10, and 15 min following intravenous administration of DDAVP, which stimulates pituitary production of ACTH. Additional samples for experimental purposes were collected immediately following the 15-min sample collection to avoid interference with the patient’s diagnostic study. 2.4 Measurement of baseline plasma S1P concentration Blood samples were obtained from both petrosal sinuses and were centrifuged to remove cellular components. Samples that exhibited hemolysis or coagulation were excluded from the study. Plasma samples were stored at −80°C. The S1P levels in plasma were analyzed using a S1P competitive ELISA kit (Echelon Biosciences, Salt Lake City, UT) according to the manufacturer’s instructions (34). 2.5 Immunofluorescence staining The pituitary tissues were post-fixed and dehydrated with alcohol as follows: 70% for 24 h, 80% for 3 h, 90% for 4 h, 95% for 3 h, and finally in absolute alcohol for 2 h. Tissue slices with a 5-μm thickness were cut using a microtome (Thermo Fisher Scientific), blocked with 3% BSA, and then treated with primary antibodies to SPHK1 (CST, #3297) and ACTH (Proteintech, CL488-66358). Subsequently, the tissue slides were incubated with Alexa Fluor 488-conjugated anti-rabbit (Invitrogen, A21206, 1:200) or Alexa Fluor 555-conjugated anti-rabbit (Invitrogen, A21428, 1:200) secondary antibodies. Specimens were visualized and imaged using a fluorescence microscope. 2.6 Statistical analysis The Mann–Whitney U test was used to assess the clinical–molecular associations in adenoma samples, whereas the chi-square test was used to compare categorical data. The Kruskal–Wallis analysis and ANOVA were conducted for multiple comparisons. Statistical analyses were conducted using SPSS v20 and GraphPad Prism version 7. All results were presented in graphs and tables as median ± interquartile range. The distribution of each parameter was presented as the minimum–maximum range. Parametric or nonparametric statistical tests were applied, as appropriate, after testing for normality. The receiver operating characteristic curve was used to determine the cut-off value for predicting tumor laterality. Pearson correlation analyses was used to examine the correlations between variables. Proportions were expressed as percentages, and significance was defined as P < 0.05. 3 Results 3.1 Clinical characteristics of remission and nonremission in patients with CD This study included 25 patients with CD who underwent BIPSS before surgery (Figure 1). Among them, 12 patients had microadenomas, whereas the remaining 13 had inconclusive magnetic resonance imaging findings; clinicopathological data are summarized in Supplementary Table 1. Table 1 displays the demographics of patients who achieved remission (n = 16) and those who did not (n = 9). No significant differences were observed in terms of sex, age at diagnosis, or radiological variables between patients who achieved and those who did not achieve remission (P > 0.05). Patients who achieved remission exhibited a higher prevalence of emotional lability (P < 0.05). However, no significant differences were observed in other parameters (P > 0.05). Figure 1 Figure 1 Flowchart of the screening process employed to select eligible participants for the study. Table 1 Table 1 Baseline clinical features of patients with pituitary tumors secreting adrenocorticotropin. Several recent studies have established morning cortisol level measured on postoperative day 1 (POD1) as a predictive biomarker for long-term remission of CD (35, 36). For biochemical features, patients who did not achieve remission exhibited higher serum cortisol (19.16 ± 5.55 vs. 5.95 ± 1.42; P = 0.014) and median serum (8 am) ACTH (10.26 ± 8.24 vs. 5.15 ± 3.68; P = 0.042) levels on POD1. No significant differences were observed in the preoperative baseline 4 pm serum cortisol levels, preoperative baseline 0 am serum cortisol levels, preoperative 8 pm ACTH levels, 4 pm ACTH levels, and 0 am ACTH levels (P > 0.05) (Table 2). In addition preoperative FT3, FT4, TSH, GH, FSH, LH, and PRL levels were comparable in patients with and without remission. Table 2 Table 2 Baseline clinical and biochemical features of patients with pituitary tumors secreting adrenocorticotropin. 3.2 Overexpression of SPHK1 and higher concentrations of serum S1P on the tumor side in patients with CD Prior studies have demonstrated that ACTH acutely activates SPHK1 to increase S1P concentrations (19). Upregulation of SPHK1 is associated with poor prognosis in endocrine-related cancer (17, 18, 21). To investigate the role of SPHK1 in CD, we performed a heatmap analysis of key genes involved in phospholipid metabolism and signaling pathways in CD adenomas and surrounding normal tissues using the GEO dataset (GEO208107). This analysis revealed the activation of crucial genes involved in phospholipid metabolism and signaling pathways in ACTH-secreting pituitary adenomas (Supplementary Figure 1). Subsequently, we compared the association between pituitary SPHK1 expression and proopiomelanocortin, corticotropin-releasing hormone, corticotropin releasing hormone receptor 1, and corticotropin releasing hormone receptor 2 in pituitary tumor tissues and identified a positive correlation between SPHK1 and ACTH tumor-related genes in the TNM plot database (Supplementary Figure 2). To investigate the potential role of SPHK1 in CD, we compared the expression values of SPHK1 in the normal pituitary tissues and those obtained from patients with CD in the remission/nonremission groups. Immunofluorescence staining (Figures 2A, B; Supplementary Figure 3) revealed an increased number of double-positive cells for SPHK1 and ACTH in CD-affected pituitary tissues than those in the normal pituitary tissues. Furthermore, the proportion of double-positive cells for SPHK1 and ACTH was significantly higher in the nonremission CD adenomas tissues than that in the remission CD adenomas. Furthermore, we investigated the concentration of S1P in bilateral petrosal sinus blood samples and observed that the concentration was significantly higher on the adenoma side than that on the nonadenoma side (397.7 ± 15.4 vs. 261.9 ± 14.88; P < 0.05, Figure 2C). Thus, these findings suggested a close association between S1P concentration and the development of ACTH-secreting tumor. Figure 2 Figure 2 (A) Representative images of immunofluorescence double staining for SPHK1 (green) and ACTH (pink) in normal pituitary glands and ACTH-secreting pituitary adenomas from the remission and nonremission groups (Normal: n = 3, ACTH pituitary adenoma: remission vs. nonremission: n = 16 vs. 9); scale bars: 100-μm upper and 50-μm lower. (B) Quantitative analysis; white arrows indicate double-positive cells for ACTH and SPHK1. (C) The concentration of S1P in the plasma obtained from the inferior petrosal sinus of the adenoma side and nonadenoma side. ***P < 0.001. Bar represents mean ± SD. 3.3 Combination of interpetrosal S1P and ACTH ratios improved the diagnostic performance for adenoma laterality The pathology of patients with CD was classified based on adenomatous tissue with ACTH-positive immunostaining into adenoma or nonadenoma sides. To evaluate the correlation between the interpetrosal S1P ratio lateralization and tumor location, we compared the accuracy of predicting tumor laterality using the interpetrosal S1P ratio (>1) and interpetrosal ACTH ratio (>1.4) (the interpetrosal ACTH ratio >1.4 is acknowledged for its positive role in predicting tumor laterality), as well as their combination. Our results indicated that using the interpetrosal S1P or ACTH ratios alone yielded accuracies of 64% and 56% respectively. Notably, the combination of both demonstrated a significantly improved accuracy of 73% (Figure 3A). Figure 3 Figure 3 (A) Bar graph illustrating the accuracy of predicting tumor laterality. (B) Receiver operating characteristic (ROC) curve analysis of interpetrosal ACTH ratio to predict tumor location. (C) ROC curve analysis of the interpetrosal S1P ratio to predict tumor location. (D) ROC curve analysis of the combination of the interpetrosal S1P and ACTH ratios to predict tumor location. Thereafter, the receiver operating characteristic analysis was performed to determine the role of predicting tumor laterality. In particular, the interpetrosal ACTH ratio with an AUC of 75.32% (95% CI: 60.06–97.46%, P < 0.05) and the interpetrosal S1P ratio demonstrated a clinically significant diagnostic accuracy for lateralization, with an AUC of 79.17% (95% CI: 44.40–85.84%, P < 0.05). Furthermore, combining the interpetrosal S1P and ACTH ratios generated an receiver operating characteristic curve with an AUC of 84.09% (95% CI: 52.3–96.77%, P < 0.05) for predicting lateralization with tumor location (cutoff value: interpetrosal S1P ratio ≥1.06, interpetrosal ACTH ratio ≥2.8, 81.82% sensitivity, and 75% specificity) (Figures 3B–D). 3.4 Interpetrosal S1P ratio serves as a predictive factor for early remission in CD To investigate whether the interpetrosal S1P ratio is associated with early postoperative remission in CD, we compared the baseline interpetrosal S1P ratio between patients with CD in the remission and nonremission groups. Interestingly, we observed that the nonremission group exhibited higher interpetrosal S1P ratios than those of the remission group (median, 1.28 ± 0.25 vs. 1.10 ± 0.09, P = 0.012) (Figure 4). Figure 4 Figure 4 Left picture: Scatter plot of bilateral S1P concentrations in the remission and nonremission groups; the slope represents the interpetrosal S1P ratio, blue dots represent the remission group, and red dots represent the nonremission group. Right picture: The interpetrosal S1P ratio in the remission and nonremission groups. *P < 0.05. Bar represents mean ± SD. To investigate potential factors affecting the interpetrosal S1P ratio, we compared the correlation between interpetrosal S1P ratio and various clinical indicators. This analysis revealed that the interpetrosal S1P ratio positively correlated with preoperative FSH and LH levels, as well as with postoperative 8 am ACTH levels. No significant difference was observed between the interpetrosal S1P ratio and other indicators (Supplementary Figure 4). 4 Discussion The use of BIPSS involves collection of samples from each inferior petrosal sinus simultaneously, enabling a direct comparison of ACTH concentrations between the left and right petrosal sinuses. BIPSS is used for two purposes: 1) to assist in the differential diagnosis of Cushing’s syndrome; and 2) to determine which side of the pituitary gland contains an adenoma in patients with CD. The interpetrosal ACTH ratio is also useful in determining the location/lateralization of pituitary microadenomas (24, 30, 37), thereby providing guidance to the neurosurgeon during surgery. To our knowledge, this is the first study to demonstrate that serum S1P levels in patients with CD are significantly higher on the adenoma side of the inferior petrosal sinus than on the nonadenoma side. The interpetrosal S1P ratio exhibited a positive significance in predicting tumor laterality, and the predictive performance was improved when S1P was combined with the interpetrosal ACTH ratio. Notably, the interpetrosal S1P ratio exhibited a positive significance in predicting remission after surgery. Furthermore, the interpetrosal S1P ratio demonstrated a positive and significant correlation with preoperative FSH and LH levels, as well as 8 am ACTH levels on POD1. ACTH is recognized for its role in controlling the expression of genes involved in steroid production and cortisol synthesis in the human adrenal cortex through sphingolipid metabolism (19). Specifically, ACTH rapidly stimulates SPHK1 activity, leading to an increased in S1P levels, which in turn, increases the expression of multiple steroidogenic proteins (20). Our study demonstrated that higher S1P concentrations were present on the tumor side than on the nontumor side in patients with CD, indicating that the regulatory relationship between ACTH and S1P also exists in ACTH-secreting pituitary adenomas. Several pieces of evidence have supported the potential relationship between S1P and the occurrence of CD. Interestingly, SPHK1 and S1P are known to be integral to the regulation of epidermal growth factor receptor (EGFR) (38), which is highly expressed in human corticotropinomas, where it triggers proopiomelanocortin (the precursor of ACTH) transcription and ACTH synthesis (39). Blocking EGFR activity with an EGFR inhibitor can attenuate corticotroph tumor cell proliferation (40). Furthermore, SPHK1 and proopiomelanocortin share a common transcriptional coactivator, P300 (41, 42). Notably, S1P also directly binds to and inhibits histone deacetylase 2, thereby regulating histone acetylation and gene expression (43). Notably, histone deacetylase 2 expression is deficient in ACTH-pituitary adenomas in CD, contributing to glucocorticoid insensitivity (44), which is a hallmark of CD and a feature associated with nonremission. These studies further demonstrated an association between high S1P ratio and nonremission of CD. Our study, for the first time, established an association between SPHK1/S1P and ACTH adenoma. Nevertheless, further experimental verification is required to confirm the existence of common pathways linking SPHK1 and ACTH. Thus, these findings indicated that the S1P ratio can, to some extent, reflect the differences in ACTH levels and may serve as a surrogate marker for detecting ACTH-secreting pituitary adenomas. BIPSS is a highly effective procedure for diagnosing pituitary sources of ACTH in CD and remains the gold standard diagnostic method. However, some findings indicated certain limitations associated with the use of the inferior petrosal sinus sampling (IPSS) method in predicting tumor lateralization. The possible causes of error include asymmetrical or underdeveloped petrosal sinus anatomy and placement of the catheter (27). The present study revealed a notable increase in the interpetrosal ACTH ratio among patients with accurate predictions of tumor laterality than among those with inaccurate predictions, although the positive predictive value remained low. These findings suggested that other mechanisms may exist that contribute to false-positive results. The limitations on lateralization highlighted the need for further research to understand the underlying mechanisms contributing to the accuracy of IPSS in predicting tumor lateralization. Further investigation is required to understand these potential mechanisms and improve the accuracy of IPSS in predicting tumor lateralization. We observed that the interpetrosal S1P ratio was slightly more effective than the ACTH ratio in predicting tumor laterality. However, combining both methods significantly improved the diagnostic sensitivity and specificity. These results have important implications for clinical practice as accurate tumor lateralization is essential for the correct management and treatment of pituitary adenomas. Overall, these findings highlighted the importance of using multiple measures in predicting tumor lateralization and suggested that combining measures may be more effective than relying on any single measure alone. Future research should investigate additional measures to improve the accuracy of tumor lateralization and optimize the use of existing measures for making clinical decisions. The initial treatment recommendation for CD is surgery. However, long-term surveillance is necessary because of the high recurrence rate (12). Therefore, identifying patients who are at a greater recurrence risk would be helpful in establishing an effective surveillance strategy. Our study revealed that the expression of SPHK1 in pituitary tissue was higher in postoperative nonremission group than in postoperative remission group. Moreover, patients in the nonremission group exhibited significantly higher interpetrosal S1P ratios than those of patients in the remission group. SPHK1 catalyzes the direct phosphorylation synthesis of S1P, and the S1P ratio can thus reflect the expression level of SPHK1 in ACTH tumors. Since S1P can increase the expression of multiple steroidogenic proteins, including steroidogenic acute regulatory protein, 18-kDa translocator protein, low-density lipoprotein receptor, and scavenger receptor class B type I (20), the interpetrosal S1P ratios may be indicative of disease prognosis. This finding is consistent with previous findings indicating the overexpression of SPHK1 is associated with poor prognosis in various neuroendocrine tumors, as factors associated with tumor proliferation, S1P and SPHK1, may play a key role in the proliferation and survival of ACTH pituitary adenomas. The high proportions of SPHK1/ACTH double-positive cells are likely associated with greater phenotypic severity, and CD tumors with this phenotype may have a poor prognosis. These findings hold clinically significance for predicting early postoperative remission in patients with CD. As aforementioned, the interpetrosal S1P ratios have been suggested as a useful diagnostic tool for determining adenoma lateralization in CD, which can also serve as a prognostic indicator for postoperative remission. Pearson correlation analysis indicated that ACTH 8 am on POD1 and FSH/LH levels were significantly associated with the interpetrosal S1P ratio, suggesting that these pituitary dysfunctions may have a role in the early remission of CD. However, the sample size in this study was relatively small, and further studies with larger sample sizes are needed to confirm these findings. Additionally, other factors affecting surgical outcomes, such as the experience of the surgeon, extent of surgical resection, and use of adjuvant therapy, should be considered when predicting postoperative remission in patients with CD. This study has some limitations. First, the study was retrospective in design, which limited the control of confounding factors. Additionally, because of the limited sample size, we did not specifically investigate cases where the ACTH ratio failed to accurately identify the correct tumor location. Finally, we did not explore the functional evidence of a common pathway between SPHK1 and ACTH. Despite these limitations, the study contributes to our understanding of the potential utility of the interpetrosal S1P ratio as a biomarker for CD and provides a basis for future research in this area. In conclusion, our study demonstrated a significant association between the interpetrosal S1P ratio and tumor laterality, as well as in early remission in CD. These findings suggested that the interpetrosal S1P ratio could serve as a useful biomarker in clinical practice. Moreover, targeting genes and drugs related to SPHK1/S1P could provide novel therapeutic strategies for treating CD. Data availability statement The original contributions presented in the study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author. Ethics statement The studies involving humans were approved by The Xiangya Hospital Ethics Committee, Xiangya Hospital (Changsha, China). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study. Author contributions HS: conceptualization, methodology, software, visualization, and investigation. CW and BH: software. YX: writing – review & editing. All authors contributed to the article and approved the submitted version. Funding The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article. Acknowledgments The authors gratefully acknowledge contributions from the GEO databases and TNMplot database (https://www.tnmplot.com/). Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Publisher’s note All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Supplementary material The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fendo.2023.1238573/full#supplementary-material References 1. Tritos NA, Miller K. Diagnosis and management of pituitary adenomas: A review. JAMA (2023) 329(16):1386–98. doi: 10.1001/jama.2023.5444 PubMed Abstract | CrossRef Full Text | Google Scholar 2. 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Genes Dev (2006) 20:2871–86. doi: 10.1101/gad.1444606 PubMed Abstract | CrossRef Full Text | Google Scholar Keywords: ipss, sphingosine-1-phosphate, Cushing’s disease, remission, tumor laterality Citation: Sun H, Wu C, Hu B and Xiao Y (2023) Interpetrosal sphingosine-1-phosphate ratio predicting Cushing’s disease tumor laterality and remission after surgery. Front. Endocrinol. 14:1238573. doi: 10.3389/fendo.2023.1238573 Received: 12 June 2023; Accepted: 17 October 2023; Published: 31 October 2023. Edited by: Anton Luger, Medical University of Vienna, Austria Reviewed by: Guangwei Wang, Hunan University of Medicine, China Marie Helene Schernthaner-Reiter, Medical University of Vienna, Austria Copyright © 2023 Sun, Wu, Hu and Xiao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. *Correspondence: Yuan Xiao, xiaoyuan2021@csu.edu.cn Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. From https://www.frontiersin.org/articles/10.3389/fendo.2023.1238573/full

Abstract Background This single-center retrospective cohort study aimed to describe the findings and validity of Bilateral inferior petrosal sinus sampling (BIPSS) in the differential diagnosis of patients with ACTH-dependent Cushing’s syndrome (CS). Methods Eleven patients underwent BIPSS due to equivocal biochemical tests and imaging results. Blood samples were taken from the right inferior petrosal sinus (IPS), left IPS, and a peripheral vein before and after stimulation with desmopressin (DDAVP). ACTH and prolactin levels were measured. The diagnosis was based on the ACTH ratio between the IPS and the peripheral vein. Also, lateralization of pituitary adenoma in patients with Cushing’s disease (CD) was predicted. No significant complications were observed with BIPSS. Results Based on the pathology report, eight patients had CD, and three had ectopic ACTH syndrome (EAS). Unstimulated BIPSS resulted in a sensitivity of 87.5%, specificity of 100%, PPV of 100%, NPV of 75%, and accuracy of 91%. Stimulated BIPSS resulted in a sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and accuracy of 100%. However, pituitary magnetic resonance imaging (MRI) had a lower diagnostic accuracy (sensitivity:62.5%, specificity:33%, PPV:71%, NPV:25%, accuracy:54%). BIPSS accurately demonstrated pituitary adenoma lateralization in 75% of patients with CD. Conclusions This study suggests that BIPSS may be a reliable and low-complication technique in evaluating patients with ACTH-dependent CS who had inconclusive imaging and biochemical test results. The diagnostic accuracy is improved by DDAVP stimulation. Pituitary adenoma lateralization can be predicted with the aid of BIPSS. Peer Review reports Introduction All disorders with manifestations associated with glucocorticoid excess are called Cushing’s syndrome. Exogenous corticosteroids cause most CS cases, and endogenous CS cases are rare [1, 2]. The diagnosis of Cushing’s syndrome may be complicated, particularly in cases with ambiguous clinical findings, atypical presentations, and cyclic hypercortisolemia [3,4,5]. The initial laboratory tests for diagnosis of CS include 24-hour urinary free cortisol (UFC), late-night salivary cortisol, and low-dose dexamethasone suppression test (DST). These tests only represent hypercortisolemia [1, 2]. Once CS is diagnosed, further evaluations are needed to identify the etiology. The first step is to measure the plasma ACTH level. A low plasma ACTH level indicates ACTH-independent CS and a high level suggests ACTH-dependent CS. Normal ACTH can also occur in ACTH-dependent CS. Almost all cases of ACTH-dependent are due to pituitary adenoma (Cushing’s disease) or EAS [1, 2, 6]. Some ectopic sources include neuroendocrine tumors, bronchial carcinoma, and pancreatic carcinoma [7, 8]. Because of the high mortality in tumors associated with EAS, it is essential to differentiate CD from EAS. To distinguish CD from EAS, a high-dose dexamethasone suppression test (HDDST), corticotropin-releasing hormone (CRH), or DDAVP stimulation tests, or pituitary MRI is recommended [1, 2, 6, 9,10,11,12]. MRI can be equivocal in half of the patients, and only relatively large lesions (> 6 mm) detected on MRI reliably confirm the diagnosis of CD with biochemical confirmation and expected clinical symptoms [9]. Considering the relatively low sensitivity and specificity of non-invasive tests [13, 14] and the high complications of the surgery, it seems reasonable to use a test with high sensitivity and specificity and few complications before resection. BIPSS with CRH or DDAVP stimulation can be helpful for further evaluation [1, 2, 10, 15, 16]. The BIPSS procedure is the same in both stimulation methods. Due to its lower cost, availability, and comparable diagnostic accuracy, using DDAVP instead of CRH for BIPSS is an alternative [17, 18]. BIPSS has been reported to have high sensitivity and specificity and is a safe procedure when performed by experienced interventional radiologists [15, 16, 19, 20]. This case series describes the experience with BIPSS and examines the validity of BIPSS for differentiating CD from EAS in patients with ACTH-dependent CS who had ambiguous or equivocal results in non-invasive tests. Materials and methods Patients This retrospective cohort study included 11 patients with ACTH-dependent CS who underwent BIPSS between 2018 and 2020 in a tertiary care hospital. Data collection Well-trained nurses conducted anthropometric measurements, including height and weight. Standing height was measured with a portable stadiometer (rounded to the nearest 0.1 cm). Using a calibrated balance beam scale, this study measured weight in the upright position (rounded to the nearest 0.1 kg). Body mass index (BMI) was calculated by dividing weight (kg) by height squared (m2). Well-trained examiners measured blood pressure (systolic and diastolic) at the left arm in the sitting position after 5 min of rest using a calibrated mercury sphygmomanometer. The blood sample was taken, and fasting blood sugar (FBS), hemoglobin (Hb), potassium (K), and creatinine (Cr) were measured. All research was performed in accordance with the Declaration of Helsinki. Informed consent was obtained from all participants or their legal guardians. Biochemical tests and imaging Patients with signs and symptoms of CS underwent screening evaluations, and confirmatory tests were performed using serum cortisol and 24-hour UFC. After confirmation of CS, ACTH was measured using an immunoradiometric assay to categorize patients into ACTH-dependent or independent groups. ACTH test was performed with SIEMENS IMMULITE 2000 device with an analytical sensitivity of 5 pg/ml (1.1 pmol/l) and CV ∼7.5%. HDDST was conducted by administering 2 mg dexamethasone every 6 h for 48 h to all patients, and then serum cortisol and 24-hour UFC were rechecked. A pituitary MRI was performed with sagittal and coronal T1- and T2-weighted images before and after the gadolinium injection. BIPSS procedure After biochemical tests and imaging, an experienced interventional radiologist performed bilateral and simultaneous catheterization of the inferior petrosal sinuses. Venography was obtained to evaluate venous anatomy and catheter placement. The retrograde flow of contrast dye into the contralateral cavernous sinuses was used as a marker of adequate sampling. After the correct placement of catheters, blood samples were obtained from each of three ports (peripheral (P), left inferior petrosal sinus (IPS), and right IPS) at -15, -10, -5, and 0 min. The current study used DDAVP for stimulation. After peripheral injection of 10 micrograms of DDAVP, blood samples from these three sites were obtained at + 3, +5, + 10, and + 15 min. Three samples from these sites were also obtained to measure prolactin. Upon collection, BIPSS samples were placed in an ice-water bath. At the end of the procedure, samples were taken to the laboratory, where the plasma was separated and used for immediate measurement of ACTH. Specimens were refrigerated, centrifuged, frozen, and assayed within 24 h. After the samples were obtained, both femoral sheaths were removed, and manual compression was used to obtain hemostasis before transferring patients to the recovery room. The whole procedure took 1–2 h. Patients underwent strict bed rest for 4 h before discharge on the same day. All BIPSS were performed without significant complications, and only hematoma at the catheterization site was observed in some patients. BIPSS interpretation The ratio of IPS ACTH to peripheral ACTH level (IPS/P ACTH) for each side was calculated. Baseline sampling at minute 0 with IPS/P ≥ 2 or stimulated sampling at minute 3 with 1PS/P ≥ 3 is confirmatory for CD [1, 8]. Also, the IPS/P ratio was checked for prolactin level after DDAVP stimulation (stimulated IPS/P prolactin). A stimulated IPS/P prolactin ≥ 1.8 indicates successful catheterization, meaning the catheter is correctly placed in the IPS [21]. For further evaluation, the current study normalized the ACTH to the prolactin level by dividing stimulated IPS/P ACTH into stimulated IPS/P prolactin for each side. A normalized ACTH/prolactin IPS/P ratio ≥ 1.3 supports a pituitary ACTH source (Cushing’s disease), and a normalized ratio ≤ 0.7 an ectopic source (EAS) [22]. The values between 0.7 and 1.3 are equivocal. The inter-sinus ratio was defined as the ratio of the IPS/P ACTH level of one side with the higher level divided by the IPS/P ACTH level of the other side with the lower level, either before or after stimulation. An inter-sinus ratio ≥ 1.4 indicates lateralization to the side with a higher IPS/P ACTH level [23]. Statistical analysis This analysis used SPSS software version 18 (SPSS, Inc.) to perform analyses. Data were expressed as numbers and percentages. Continuous variables were presented as means (± SD). This study reported the median or range when the data did not follow a normal distribution. The Shapiro-Wilk test was used to test for normality. The nonparametric Mann-Whitney U Test was utilized to compare variables. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the tests were calculated based on standard statistical equations. Results Baseline characteristics and clinical manifestations This retrospective research studied 11 patients with ACTH-dependent CS, including eight females (72.7%) and three (27.3%) males. The median (Q1-Q3) age was 32.0 (22–45) years. The median (Q1-Q3) of BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), FBS, Hb, K, and Cr were 29.2 (24.8–33.3), 130.0 (125–140), 80.0 (80–95), 98.0 (88–103), 13.5 (12.4–13.9), 4.2 (3.9–4.5), and 1.0 (0.9–1.1), respectively. The demographic characteristics of patients are presented in Table 1. The Hb levels were not different in women and men (median 13.35 vs. 13.70, p-value = 0.776). In addition, no statistical difference between patients with a final diagnosis of CD and EAS was detected for Hb levels (Total: median 13.60 vs. 13.2, p-value > 0.05) (Women: median 13.5 vs. 13.2, p-value > 0.05) (Men: median 13.7 vs. 13.25, p-value > 0.05). Table 1 Demographic characteristics of the studied patients Full size table 90% of patients had at least one skin manifestation, such as striae, easy bruising, acne, hyperpigmentation, hirsutism, hair loss, edema, and hypertrichosis. Other symptoms were hypertension (HTN) (81%), reproductive dysfunction (81%), including infertility, oligomenorrhea, loss of libido, weight gain (72%), proximal muscle weakness (45%), and headache (27%) (Table 2). Table 2 Clinical manifestations of the studied patients Full size table Results of biochemical tests Biochemical tests results, including basal serum cortisol (median:26 mcg/dl, range:15-54.5 mcg/dl), basal 24-hour UFC (median:670 mcg/dl, range:422–1545 mcg/dl), ACTH (median:58.8 pg/ml, range:25–155 pg/ml), serum cortisol after HDDST (median:14.2 mcg/dl, range:2.63-36.0 mcg/dl), 24-hour UFC after HDDST (median:292 mcg/dl, range:29.5–581 mcg/dl) are presented in Table 3. According to the basal serum cortisol results, eight patients (Cases 1, 3, 5, 7, 8, 9, 10, and 11) had basal serum cortisol levels > 22 mcg/dl, which indicates hypercortisolemia. Other patients (Cases 2, 4, and 6) had basal serum cortisol in the normal range (5–25 mcg/dl) and were considered as false negative results of this test. Table 3 The results of biochemical tests in the studied patients Full size table All patients had elevated basal 24-hour UFC levels (422–1545 mcg/dl), indicative of hypercortisolemia (Table 3). There were six patients with elevated peripheral ACTH levels (> 58 pg/ml) (cases 5, 6, 8, 9, 10, and 11). Other patients had ACTH within the normal range (6–58 pg/ml) (cases 1, 2, 3, 4, 7) (Table 3). None of the patients showed suppression after 1 mg DST. After HDDST, cases 2, 3, 8, and 10 had more than 50% suppression of serum cortisol. In the other six patients, serum cortisol was not suppressed or suppressed by less than 50%. In one patient, serum cortisol levels were not measured (case 1) because the sample was not stored under standard test conditions. Also, eight patients had more than 50% 24-hour UFC suppression after HDDST (cases 1, 2, 3, 4, 6, 7, 9, and 10). In two patients, 24-hour UFC was suppressed less than 50% (cases 5 and 11), and in one patient (case 8), the 24-hour UFC sample was not tested due to the non-standard condition of the sample. BIPSS results BIPSS results before and after stimulation are shown in Table 4. The baseline value (sampling at minute 0) of IPS/P ACTH ≥ 2 confirms CD. According to this ratio, cases 1,3,4,5,6,7, and 8 were diagnosed as CD. The unilateral source for CD was confirmed in cases 1, 3, 7, and 8. BIPPS didn’t demonstrate lateralization in cases 4, 5, and 6. Table 4 Baseline and stimulated IPS/P ratio for ACTH and Prolactin in the studied patients Full size table The highest IPS/P ACTH ratio was 3 min after the DDAVP injection. A sampling at minute 3 with stimulated IPS/P ACTH ≥ 3 confirms CD. This ratio confirmed CD in cases 1–8 and showed a unilateral source for CD in cases 1, 2, 3, and 7. The ratio didn’t demonstrate lateralization in cases 4, 5, 6, and 8. The stimulated IPS/P prolactin was ≥ 1.8 in all cases. The variability in the IPS/P ACTH ratio in patients with CD is shown in Fig. 1. The peak of this ratio was 3 min after the DDAVP injection. In patients with EAS, there were no changes before or after the DDAVP stimulation. Fig. 1 Comparison of mean values of IPS/P ACTH in CD (Lt.) and EAS (Rt.). IPS; inferior petrosal sinus; P: peripheral; ACTH: adrenocorticotropic hormone; CD: Cushing’s disease; EAS: ectopic ACTH syndrome; Lt: left; Rt: right Full size image According to the Prolactin-normalized ACTH IPS/P ratios, eight patients (cases 1–8) were diagnosed as CD and three as EAS (cases 9–11). In cases 1, 2, 3, 7, and 8, unilateral sources of CD were confirmed, but in cases 4,5 and 6, bilateral sources were detected (Table 4). According to the inter-sinus ratio, BIPSS could lateralize the source of ACTH in all patients with CD. The inter-sinus ratio in patients with EAS could not lateralize any pituitary source for ACTH (Table 4). In five patients with CD and one with EAS, the highest peripheral ACTH level was observed 15 min after stimulation. Two patients with CD and one with EAS had the highest peripheral ACTH level 10 min after stimulation. Only one patient with CD and one with EAS had the highest peripheral ACTH level 5 min after stimulation. No patient had maximum peripheral ACTH levels in the first post-stimulation sample (minute 3). The larger numerator or smaller denominator produces a higher value in a ratio. In the samples obtained immediately after stimulation, the highest concentration of ACTH was in the IPS, and the lowest was in the peripheral blood. Therefore, as mentioned, the highest post-stimulation value of the IPS/P ACTH ratio was obtained at minute 3. MRI results MRI results showed pituitary adenoma in five patients, enhancement in one patient, pituitary mass and lesion in two patients, empty sella in two patients, and possible pituitary adenoma and adrenal mass in one patient (Table 5). Table 5 Final diagnosis, lateralization, MRI results, and management Full size table Immunohistochemistry (IHC) results According to the pathology report, eight patients were confirmed as CD (Table 5). The other two patients were EAS (one carcinoid tumor of the lung and one pheochromocytoma). One patient had no documented pathologic source of hypercortisolemia because the patient did not consent to surgery, and the diagnosis of EAS was made based on the results of biochemical tests. BIPSS vs. MRI results MRI results showed pituitary adenoma in five patients with CD. MRI and BIPSS showed the adenoma on a similar side in two of them. In the other three patients, MRI showed bilateral adenoma, but BIPSS lateralized the adenoma to one side. One of the other three patients had only left-sided enhancement but no overt adenoma on MRI, whereas BIPSS lateralized the adenoma to the right side. One patient had a low-signal pituitary mass on the right side on MRI, and BIPSS also lateralized to the right. Another patient with a history of transsphenoidal surgery (TSS), diagnosed as recurrent CD, had a partially empty sella. MRI was equivocal, but BIPSS lateralized to the left side. Among patients with EAS, one with an equivocal BIPSS result had an empty sella on MRI. Two other patients had pituitary lesions on MRI, but BIPSS results were equivocal. Comparison between BIPSS, MRI, and surgery Among patients with CD, the final diagnosis based on surgery in three patients was consistent with MRI and BIPSS results and lateralized the adenoma on the same side. In one patient, the surgery result was similar to the MRI findings and showed bilateral adenoma, but BIPSS showed adenoma on the left side. In the patient with equivocal MRI findings and a history of TSS, IHC could not identify ACTH +, although BIPSS lateralized to the left side. In three other patients, surgery results were concordant with BIPSS and lateralized the adenoma on the same side, although MRI showed discordant results. Validity of BIPSS Baseline IPS/P ACTH resulted in a sensitivity of 87.5%, specificity of 100%, PPV of 100%, NPV of 75%, and accuracy of 91%. Stimulation with DDAVP improved validity. Both stimulated IPS/P ACTH and normalized ACTH/prolactin IPS/P ratio resulted in a sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and accuracy of 100%. BIPSS, either unstimulated or stimulated, had higher validity than MRI, with a sensitivity of 62.5%, specificity of 33%, PPV of 71%, NPV of 25%, and accuracy of 54%. BIPSS accurately predicted pituitary adenoma lateralization in 75% of patients with CD. Discussion In this study, BIPSS before stimulation showed a sensitivity of 87.5% and a specificity of 100%. However, BIPSS after stimulation showed a sensitivity of 100% and specificity of 100%. It has been demonstrated that the sensitivity of BIPSS can vary from 88 to 100%, and its specificity from 67 to 100% in the diagnosis of CD [24]. Previous studies have reported sensitivity and specificity of more than 80% and 90% for BIPSS, and the combination of BIPSS with stimulation by CRH or DDAVP improves the sensitivity and specificity to more than 95 and 100%, respectively [15, 19, 25]. Chen et al. suggested the optimal IPS:P cutoff value of 1.4 before and 2.8 after stimulation [20]. Considering these cutoffs, the only patient in this study who was negative for CD before stimulation becomes positive, and the sensitivity before stimulation increases from 87.5 to 100%. The diagnostic accuracy after stimulation remains unchanged. Results of the current study showed that BIPSS is highly valued in final diagnosis, even without stimulation. In this investigation, the utilization of Prolactin-normalized ACTH IPS/P ratios exhibited a sensitivity and specificity of 100% for the CD diagnosis. This finding aligns with research conducted by Detomas et al., which reported a sensitivity of 96% and specificity of 100% for the normalized ACTH: Prolactin IPS/P ratio [26]. It seems that concurrently assessing prolactin levels may potentially enhance the diagnostic accuracy of BIPSS. However, the current literature is inconsistent. Some studies do not support the use of prolactin to diagnose CD [27]. In all patients, the IPS/P ACTH ratio at minute 15 did not show a considerable difference from this ratio at minute 0. Previous studies have shown that sampling at minute 15 is not helpful for diagnosis [1, 15, 20, 28]. Unlike the IPS/P ACTH ratio, six patients had the highest peripheral ACTH level at minute 15 after stimulation, but no patient had it at minute 3 after stimulation. However, more studies are needed to obtain more precise results, and this study’s sample size was limited. BIPSS accurately lateralized the adenoma in six patients with CD, but MRI was able to lateralize the adenoma in two patients correctly. BIPSS had higher validity than MRI in differentiating CD from EAS, both with and without stimulation. The current literature is controversial. Colao et al. reported that adenoma could be accurately localized in 65% of patients using IPSS [23]. However, Lefournier et al. showed that the diagnostic accuracy of IPSS in identifying the side of the pituitary adenoma was 57% [28]. Wind et al. showed that the PPV for IPSS to identify the tumor side correctly was 69%. Additionally, MRI was more accurate than IPSS in tumor lateralization [29]. Earlier studies have shown that MRI may show a pituitary lesion, and BIPSS indicates a pituitary adenoma. However, the lesion observed on the MRI is not related to the pituitary adenoma [1, 15, 19, 25, 28]. Also, MRI may show pituitary lesions, while BIPSS indicates EAS. In the current study, the concordance of IHC results with BIPSS and MRI findings was inconclusive, possibly due to the limited number of patients. However, there is disagreement about the role of pathological study in diagnosis [19, 28]. Eight patients had elevated basal serum cortisol levels in this study (Sensitivity:73%). Instead, all patients had hypercortisolemia according to basal 24-hour UFC results, and no false-negative results were observed (Sensitivity:100%). This study’s findings were consistent with previous studies regarding low sensitivity for basal serum cortisol and high sensitivity for 24-hour UFC as screening tests for hypercortisolemia [6, 30, 31]. After HDDST, basal serum cortisol suppression was observed in three patients with CD (cases 2, 3, and 😎 but not in the others with CD. Also, serum cortisol levels were suppressed after HDDST in a patient with EAS who had a lung carcinoid tumor. Arnaldi et al. showed that some carcinoid tumors might be sensitive to HDDST, and suppression of serum cortisol may be observed after this test [1, 32]. After HDDST, six patients with CD had suppressed 24-hour UFC, but one did not show more than 50% suppression. Two patients with EAS had more than 50% 24-hour UFC suppression. According to the final pathology report, the sensitivity of serum and urine cortisol level tests after HDDST was 43% and 86%, and the specificity was 67% and 33%, respectively. PPV in both was 75%, NPV was 33% and 50%, and accuracy was 50% and 70%, respectively, which shows that these preliminary tests cannot be a good guide for the final diagnosis and subsequent treatment planning. Previous studies showed that more than one biochemical test could improve the accuracy for differentiating between CD and EAS [1, 5, 6, 9, 31]. The current study confirms the importance of using more than one biochemical test for diagnosing hypercortisolemia and diagnosing CD from EAS. Detomas et al. reported that Hb levels were high in females with CS while they were low in males with CS. Furthermore, there were lower levels of Hb in EAS than in CD in females [33]. In the current study, the Hb levels were not different in women and men. Furthermore, no statistical difference was observed for Hb levels between patients with a final diagnosis of CD and EAS. Hb levels did not contribute to diagnosing ACTH-dependent CS in this analysis. There were some limitations in this study. First, the sample size was relatively small. Second, it was a retrospective study. Further studies could investigate the BIPSS in a larger sample size and determine the validity of this method in patients with CS. Conclusions The current study suggests that BIPSS can be a reliable and low-complication method in evaluating patients with ACTH-dependent CS who had equivocal results in imaging and biochemical tests, even before stimulation. Stimulation with DDAVP increases diagnostic accuracy. BIPSS can be used to predict the lateralization of the pituitary adenoma. Data Availability All data generated or analyzed during this study are included in this published article. Abbreviations BIPSS: Bilateral inferior petrosal sinus sampling ACTH: Adrenocorticotropic hormone CS: Cushing’s syndrome IPS: Inferior petrosal sinus DDAVP: Desmopressin CD: Cushing’s disease EAS: Ectopic ACTH syndrome MRI: Magnetic resonance imaging UFC: Urinary free cortisol DST: Dexamethasone suppression test HDDST: High-dose dexamethasone suppression test CRH: Corticotropin-releasing hormone BMI: Body mass index FBS: Fasting blood glucose Hb: Hemoglobin Cr: Creatinine PPV: Positive predictive value NPV: Negative predictive value SBP: Systolic blood pressure DBP: Diastolic blood pressure K: Potassium HTN: Hypertension IHC: Immunohistochemistry TSS: Transsphenoidal surgery References Arnaldi G, Angeli A, Atkinson A, Bertagna X, Cavagnini F, Chrousos G, et al. Diagnosis and Complications of Cushing’s syndrome: a consensus statement. J Clin Endocrinol Metabolism. 2003;88(12):5593–602. Article CAS Google Scholar Sharma ST, Nieman LK, Feelders RA. 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Author information Authors and Affiliations Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran Mohammadali Tavakoli Ardakani, Soghra Rabizadeh, Amirhossein Yadegar, Fatemeh Mohammadi, Sahar Karimpour Reyhan, Reihane Qahremani, Alireza Esteghamati & Manouchehr Nakhjavani Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran Hossein Ghanaati Contributions MN and MTA and SR: Conception and design of the study. AY and FM and HG: Acquisition of data. MTA and AY and SR: Analysis and interpretation of data. FM and RQ and SK: Drafting the article. MN and AE and AY: Critical revision of the article. All authors read and approved the final manuscript. Corresponding author Correspondence to Manouchehr Nakhjavani. Ethics declarations Ethics approval and consent to participate This study was performed in line with the principles of the Declaration of Helsinki. Informed consent was obtained from all participants or their legal guardians. Approval was granted by the Research Ethics Committee of Tehran University of Medical Sciences (Approval number: IR.TUMS.MEDICINE.REC.1398.707). Consent for publication In order to publish this study, written informed consent was obtained from each participant. A copy of the written consent form is available for review by the journal editor. Competing interests The authors declare no competing interests. Additional information Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Rights and permissions Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Reprints and Permissions Cite this article Ardakani, M.T., Rabizadeh, S., Yadegar, A. et al. Bilateral inferior petrosal sinus sampling: validity, diagnostic accuracy in lateralization of pituitary microadenoma, and treatment in eleven patients with Cushing’s syndrome – a single-center retrospective cohort study. BMC Endocr Disord 23, 232 (2023). https://doi.org/10.1186/s12902-023-01495-z Download citation Received05 July 2023 Accepted19 October 2023 Published23 October 2023 DOIhttps://doi.org/10.1186/s12902-023-01495-z Share this article Anyone you share the following link with will be able to read this content: Get shareable link Provided by the Springer Nature SharedIt content-sharing initiative Keywords BIPSS Bilateral inferior petrosal sinus sampling Cushing’s Disease Cushing’s syndrome EAS From https://bmcendocrdisord.biomedcentral.com/articles/10.1186/s12902-023-01495-z

Context: Intensity-modulated radiotherapy (IMRT) is a modern precision radiotherapy technique for the treatment of the pituitary adenoma. Objective: Aim to investigate the efficacy and toxicity of IMRT in treating Cushing’s Disease (CD). Methods: 70 of 115 patients with CD treated with IMRT at our institute from April 2012 to August 2021 were included in the study. The radiation doses were usually 45-50 Gy in 25 fractions. After IMRT, endocrine evaluations were performed every 6 months and magnetic resonance imaging (MRI) annually. Endocrine remission was defined as suppression of 1 mg dexamethasone test (DST) or normal 24-hour urinary free cortisol level (24hUFC). The outcome of endocrine remission, endocrine recurrence, tumor control and complications were retrieved from medical record. Results: At a median follow-up time of 36.8 months, the endocrine remission rate at 1, 2, 3 and 5 years were 28.5%, 50.2%, 62.5% and 74.0%, respectively. The median time to remission was 24 months (95%CI: 14.0-34.0). Endocrine recurrence was found in 5 patients (13.5%) till the last follow-up. The recurrence-free rate at 1, 2, 3 and 5 years after endocrine remission was 98.2%, 93.9%, 88.7% and 88.7%, respectively. The tumor control rate was 98%. The overall incidence of new onset hypopituitarism was 22.9%, with hypothyroidism serving as the most common individual axis deficiency. Univariate analysis indicated that only higher Ki-67 index (P=0.044) was significant favorable factors for endocrine remission. Conclusion: IMRT was a highly effective second-line therapy with low side effect profile for CD patients. Endocrine remission, tumor control and recurrence rates were comparable to previous reports on FRT and SRS. Introduction Cushing’s disease (CD) is characterized by hypersecretion of adrenocorticotropic hormone (ACTH) from pituitary adenoma. As the state of hypercortisolemia considerably increases morbidity and mortality, normalizing cortisol levels is regarded as the major treatment goal in patients with CD (1). Transsphenoidal selective adenomectomy (TSS) is now established as the first-line treatment of CD. Despite the satisfactory remission rate that can be achieved with TSS (ranging from 59-97%), delayed recurrences have also been reported in up to 50% of patients (2). The Endocrine Society guidelines suggest a shared decision-making approach in patients who underwent a noncurative surgery or for whom surgery was not possible (3). Second-line therapeutic options include repeat transsphenoidal surgery, medical therapy, radiotherapy and bilateral adrenalectomy. Radiotherapy (RT) is generally used in patients who have failed TSS or have recurrent CD, as well as in progressively growing or invasive corticotroph tumors (3, 4). Both stereotactic radiosurgery(SRS)and fractionated radiotherapy (FRT) have been used in the treatment of CD. Conventional radiotherapy as one of the technique for FRT has been used with a long experience, but its benefits were hindered by high risk of toxicity, mainly attributed to the harm to healthy surrounding structures (4). Previous studies on conventional RT in treating CD showed high efficacy (tumor control rate of 92-100% and hormonal control rate of 46-89%), but RT-induced hypopituitarism (30-58%) and recurrence (16-21%) were also commonly reported (1, 4–7). Modern precise radiotherapy, especially intensity-modulated radiotherapy (IMRT), can spare the surrounding normal structure better by a more conformal and precise dose distribution (8). However, a large cohort study on long-term efficacy and toxicity of IMRT for CD is still lacking. Therefore, in the current study, we aim to analyze the efficacy and toxicity of intensity-modulated radiotherapy (IMRT) in treating CD. We also investigated the predictors of endocrine remission in aid of further management. Methods Patient We collected 115 cases of Cushing’s disease treated at our center from April 2012 to August 2021. Patients were excluded under the following conditions: (1) follow-up time less than 3 months, (2) lacking evaluation of serum cortisol (F), adrenocorticotropic hormone (ACTH) or 24-hour urinary free cortisol (24hUFC) before or after RT, (3) underwent uni or bilateral adrenalectomy, (4) having received RT at other institutes before admitted to our center. At last, a total of 70 cases were included in this study. Radiotherapy parameters RT was administrated by a linear accelerator (6 MV X-ray). Intensity-modulated radiation therapy was applied for all patients. Including fix-filde IMRT (FF-IMRT), volumetric modulated arc therapy (VMAT) or Tomotherapy. We immobilized the patient with an individualized thermoplastic head mask and then conducted a computed tomography (CT) simulation scan at 2- to 3-mm intervals. The target volume and organs at risks (OARs) were delined with a contrast enhanced T1-weighted image (T1WI) magnetic resonance imaging (MRI) fusing with planning CT. The gross tumor volume (GTV) was defined with the lesion visible on MRI or CT. The clinical target volume (CTV) included microscopic disease, especially when the tumor invaded cavernous sinus and surrounding bones. The planning target volume (PTV) was defined as CTV plus a margin of 2- to 3-mm in three dimensions. The prescription dose was defined at 100% isodoseline to cover at least 95% PTV. The maximum dose was limited to less than 54 Gy for the brain stem and optic pathway structures. Radiotherapy was performed once a day and five fractions a week during five to six weeks. The total dose was 45-60 Gy, delivered in 25-30 fractions, with most patients (78.6%) receiving 45-50 Gy in 25 fractions. The fractionated dose was 1.8-2.0 Gy. Data collection and clinical evaluation Baseline characteristics were collected at the last outpatient visit before RT, including demographic characteristics, biochemical data, tumor characteristics and details of previous treatments. After RT, endocrine evaluations were performed every 6 months. Endocrine remission was considered when 1 mg dexamethasone suppression test (DST)<1.8 mg/dl. If 1mg DST results were lacking, then 24hUFC within the normal range was used as a remission criterion. Patients who regained elevated hormone levels after achieving remission were considered to have endocrine recurrence. For patients receiving medications that could interfere with the metabolism of cortisol, hormonal evaluation was performed at least 3 months after the cessation of the therapy. Tumor size was measured on magnetic resonance imaging (MRI) before RT and annually after the completion of RT. Any reduction in or stabilization of tumor size was considered as tumor control. Tumor recurrence was defined as an increase of 2 millimeters in 2 dimensions comparing to MRI before RT, or from invisible tumor to a visible tumor on MRI (9). Anterior pituitary function was assessed before RT and every 6 months during the follow-up after RT. RT-induced hypopituitarism was defined as the development of new onset hormone deficiency after RT. The diagnostic criteria for growth hormone deficiency (GHD), central hypothyroidism and hypogonadotropic hypogonadism (HH) refer to previous literature (10–12). Panhypopituitarism referred to three or more anterior pituitary hormone deficiencies (13). Statistical analysis Statistical analysis was performed with SPSS version 25.0. Longitudinal analysis was performed with Kaplan-Meier method. For time-dependent variable, Log rank test was used for univariate analysis and Cox regression for multivariate analysis. The cut-off of F, ACTH and 24hUFC were defined as their median value. All variants in the univariate analysis were included in the model of multivariate analysis. P value < 0.05 was considered statistically significant. Plot was created with GraphPad Prism version 9.4. Results Patient characteristics Of 70 cases included in the study, the median age was 32 years (range, 11-66 years). 60 (85.7%) were female and 10 (14.3%) were male (F:M= 6:1). The median follow-up time was 36.8 months (range, 3.0-111.0 months). 68 patients received RT as a second-line treatment because of incomplete tumor resection, failure to achieve complete endocrine remission or recurrence postoperative, and 2 were treated with RT alone because of contraindication of surgery. The frequency of surgical treatment was 1 for 42 patients, 2 for 21 and more than 3 for 5. A total of 8 patients received medical treatment before RT. 5 of them used pasireotide, 2 used ketoconazole and 1 used mifepristone. The median ACTH level was 58.7 pg/ml (range 14.9-265 pg/ml), F, 26.2μg/dl (range 11.8-72.6 μg/dl) and 24hUFC, 355.7 μg/24hr (range 53.5-3065 μg/24hr) before RT. Tumor size evaluation was performed in all 70 patients before RT. Among them, 36 patients showed no visible residual tumor identified on MRI and only 5 patients showed tumor size more than 1 cm. Hypopituitarism was found in 31 patients (38.8%) before RT. HH was the most common (21 patients, 26.3%), followed by central hypothyroidism (13 patients, 16.3%) and GHD (9 patients, 11.3%). Panhypopituitarism was found in 4 patients (5.0%). (Table 1). Table 1 Table 1 Patient characteristics. Endocrine remission Endocrine remission was achieved in 37 of 70 patients during the follow-up. Six of them were evaluated by 1mg DST. The hormonal remission rate at 1, 2, 3 and 5 years were 28.5%, 50.2%, 62.5% and 74.0%, respectively, gradually increasing with follow-up time (Figure 1). The median time to remission was 24.0 months (95%CI: 14.0-34.0 months). Univariate analysis indicated that only higher Ki-67 index (P=0.044) was significant favorable factors for endocrine remission. There was no significant correlation between remission and age, sex, tumor size, the frequency of surgery, medication prior RT. The hormone levels (F, ACTH and 24hUFC prior RT) were divided into high and low groups by the median value, and were also not found to be associated with endocrine remission (Table 2). Since only Ki-67 was significant in the univariate analysis and all other parameters were far from significant, a multivariate analysis was no longer performed. Figure 1 Figure 1 Endocrine remission rate during the follow-up after RT. Table 2 Table 2 Univariate predictors of endocrine remission. Endocrine recurrence was found in 5 patients till the last follow-up, with an overall recurrence rate of 13.5% (5/37). The median time to recurrence after reaching endocrine remission was 22.5 months. The recurrence-free rate at 1, 2, 3 and 5 years after endocrine remission was 98.2%, 93.9%, 88.7% and 88.7%, respectively (Figure 2). Figure 2 Figure 2 Recurrence free rate after endocrine emission. Tumor control A total of 51 patients had repeated MRI examinations before and after treatment. During the follow-up, 20 patients showed reduction and 30 patoents remained stable in tumor size, with a tumor control rate of 98%. Only 1 patient showed enlargement tumor 1 year after RT, with F, ACTH and 24hUFC increase continuously. Complications At the last follow-up, 16 patients developed new onset hypopituitarism after RT. The overall incidence of RT-induced hypopituitarism was 22.9%. Hypothyroidism was the most common of hypopituitarism (8 patients), followed by HH (7 patients), adrenal insufficiency (4 patients) and GHD (3 patients). Only 1 patient (1.3%) with systemic lupus erythematosus (SLE) comorbidity complained of progressively worsening visual impairment during the follow up. No cerebrovascular event or radiation associated intracranial malignancy was found in our cohort. Discussion Efficacy and radiotherapy techniques RT has been emerged as an effective second-line treatment for CD for many years. Although conventional fractionated RT has been used for a long experience in patients with CD, study on the modern precise radiotherapy, particularly IMRT, is rare and reports limited evidence on its long-term treatment outcome. IMRT can be implemented in many different techniques, such as fixed-field intensity-modulated radiotherapy (FF-IMRT), volumetric-modulated arc therapy (VMAT) and tomotherapy. Compared with conventional RT, IMRT allows a better target volume conformity while preserves adequate coverage to the target (14, 15). Our study reported that IMRT for CD has an endocrine remission rate of 74.0% at 5 years, with a median time to remission of 24.0 months (95%CI: 14.0-34.0 months). The endocrine remission rate at 5 years was comparable to those reported in previous series of FRT, with a median time to remission within the reported range (4.5-44 months) (9, 16–18) (Table 3). Compared with SRS in treating CD, the endocrine remission rate and median time to remission were also similar. Pivonello et al (19) summarized 36 studies of SRS for CD between 1986 to 2014, the mean endocrine remission rate was 60.8% and the median time to remission was 24.5 months. Tumor control rate was 98% in our cohort, only one patient showed enlargement tumor with elevating hormones. This local control rate was also comparable to that reported in a series of pituitary adenoma treated with FRT (93-100%) and SRS(92-96%) (9, 16–18, 20, 21). Indeed, despite the lack of controlled studies about SRS and FRT in treating CD, many reviews that summarize the biochemical control and tumor contral of both are similar (2, 6, 19). Table 3 Table 3 Literature review of FRT and SRS in patients with CD published in recent years. The overall endocrine recurrence rate in our study was 13.5%, with a median time to recurrence of 22.5 months. We, for the first time, reported the actuarial recurrence free rate at 1, 2, 3 and 5 years in CD patients treated with IMRT. The recurrence free rate at 3 and 5 years was 88.7% in our study. Outcomes were comparable to those reported in patients treated with conventional RT or SRS, with a mean recurrence rate and a median recurrence time of 15.9% (range, 0-62.5%) and 28.1 months, or 12.3% (range, 0-100%) and 33.5 months, according to a review conducted by Pivonello et al (19). At 2020, we reported the outcomes of pituitary somatotroph adenomas treated with IMRT at our institution (20). Compared with pituitary somatotroph adenomas, CD has a similar 5-year remission rate (74.0% vs 74.3%) but a shorter median time to remission (24.0m vs 36.2m) (Figure 3). The tumor contral rates were similar, at 98% and 99%, respectively. The endocrine recurrence rate was significantly different, with CD being about one-fold higher than the pituitary somatotroph adenoma (13.8% vs 6.1%). This may be due to the majority of microadenomas in CD and that of macroadenomas in pituitary somatotroph adenomas. Figure 3 Figure 3 Endocrine remission rate of CD and pituitary somatotroph adenoma. Predictors of endocrine remission In the univariate analysis, we found that only Ki-67 index ≥ 3% was correlated with better endocrine remission (p=0.044). Cortisol levels before RT and tumor size were not predictors of endocrine remission. For surgery in treating CD, higher preoperative ACTH level was considered as unfavorable prognostic factor for endocrine remission in a few studies (22, 23). For radiotherapy, some previous studies also have reported a faster endocrine remission in patients with lower serum cortisol level. Minniti et al. reported that hormone level was normalized faster in patients with lower urinary and plasma cortisol level at the time of RT (16). Apaydin also reported that low postoperative cortisol and 1mg DST was a favorable factors for faster remission in patients treated with gamma knife surgery (GKS) and hypofractionated radiotherapy (HFRT), although no significant relationship was found between remission rate and plasma cortisol level prior RT in both studies (9, 16). Castinetti et al. found that initial 24hUFC was a predicative factor of endocrine remission in patients treated with GKS, which was not reported in our cohort treated with IMRT (24). However, the discrepancy between the results can be attributed to various factors, including selection bias of retrospective study, duration of follow-up, endocrine remission criteria and cut-off value. Tumor size before RT was considered as a significant predictor for endocrine remission in some published series of patients treated with SRS. Jagannathan et al. reported a significant relationship between preoperative tumor volume and endocrine remission in patients with CD treated with GKS (25). However no significant correlation between tumor size and endocrine remission was found in series of patients treated with FRT (5, 9, 16, 17). But our study found no significant correlation between tumor size (visible or no-visible residual tumor on MRI) before RT and endocrine remission. The frequency of surgery before RT was also not found to be associated with endocrine remission in our study, which reached a similar conclusion with some previous studies (9, 17, 18, 26). Abu Dabrh et al. reported a higher remission rate in patients receiving TSS prior RT in their meta-analysis (5). Similar result was also reported in a review on the treatment outcome of GKS in patients with CD, that postoperative GKS was more effective than primary GK (19). However, analysis on this parameter was difficult in our cohort considering the low number of patients who received IMRT as the first-line treatment. Reports on the effect of medical treatment on endocrine remission have been controversial. Some studies reported a negative effect of medical treatment at the time of SRS on endocrine remission in patients with CD. Castinetti et al. showed a significant higher rate of endocrine remission in patients who were not receiving ketoconazole at the time of GKS, compared to those who were (27). Sheehan et al. also found a significantly shorter time to remission in patients who discontinued ketoconazole at the time of GKS (28). However, no such correlation was found in patients treated with FRT (9, 17). Like previous studies on FRT, we also noted no significant relationship between preradiation use of medication and endocrine remission, but our statistical analysis may be hindered by the low proportion of patients undergoing medical treatment before RT. Moreover, the anticortisolic drugs used in previous studies were mainly ketoconazole or cabergoline, while most of our patient have received pasireotide, whose effect have not been well-studied yet. Further studies are necessary to understand the effect of somatostatin receptor ligands on the outcome of radiotherapy in patients with CD. Complications Hypopituitarism is the most common complication secondary to radiotherapy, with the rate of new-onset hypopituitarism ranging widely in previous report. Pivonello et al. reviewed series of CD patients who were treated with conventional RT with a follow-up of at least 5 years (19). The reported mean and median rates of hypopituitarism were 50% and 48.3%, respectively (range, 0-100%). As regards FRT, the overall rate of new-onset hypopituitarism was 22.2-40% at a median follow-up ranging from 29-108 months, with both incidence and severity increasing with longer follow-up (9, 16–19). The incidence of hypopituitarism in our series was 22.9%, which was within the reported range of new onset hypopituitarism after FRT. Lower rate of hypopituitarism after SRS compared to conventional RT has been recognized in previous reviews (2, 6). Our study showed that new onset hypopituitarism was less prevalent after IMRT than after conventional RT. This can be attributed to a higher precision in contouring the target volume and OARs, allowing these modern radiotherapy techniques to provide a better protection to hypothalamus-pituitary axes. In previous studies, potential risk factors for new onset hypopituitarism included suprasellar extension, higher radiation dose to the tumor margin and lower isodose line prescribed (29, 30). Sensitivity of individual hormonal axes to RT varies in different series. In our study, central hypothyroidism was the most common individual axis deficiency, followed by HH, adrenal insufficiency and GHD. This sequence was similar to that reported by Sheehan et al., whose series included 64 CD patients treated with SRS, as well as some other series (29, 31). It is noted in some studies that GHD is the most vulnerable axes (19, 32, 33). Limited number of patients undergoing stimulation test may underestimate the prevalence of GHD in our study and some previous series, and longer follow-up is needed to generate a more accurate, time-dependent rate of new onset hypopituitarism. In our study, only one patient complained of mild visual impairment, which was comparable to the rate ranging from 0-4.5% in previous series of FRT treating pituitary adenoma (9, 16–18, 26, 32, 34, 35). This patient had concomitant SLE and the associated microangiopathy may render the optic nerve intolerant to radiotherapy. Cranial nerve damage was acknowledged as an uncommon complication, with an estimated risk of vision deterioration below 1% if single radiation dose was no more than 2.0 Gy and total dose no more than 45-50 Gy (2, 36). The actuarial rate of optic neuropathy at 10 years was 0.8% in a series containing 385 patients with pituitary adenoma (37). No patient in our cohort developed cerebrovascular accident or secondary brain tumor. This finding was consistent with the low actuarial prevalence of these complications reported in other published series of FRT. Secondary brain tumor was extremely rare after SRS, with an overall incidence of 6.80 per patients-year, or a cumulative incidence of 0.00045% over 10 years in a multicenter cohort study containing 4905 patients treated with GKS (38). Ecemis et al. reviewed cohort studies of conventional RT in treating pituitary adenoma from 1990 to 2013 and found that 1.42% of patients developed secondary brain tumor, with a latency period of 19.6 years for meningioma, 11 years for glioma and 9 years for astrocytoma (39). As for cerebrovascular accident, Minniti et al. reported two patients (in a total of 40 patients) who had stroke 6 and 8 years after FRT (16). Data was still limited for FRT. Considering the low incidence and long latency period, large, controlled cohort study with long follow-up of FRT is still needed to accurately evaluate these complications. Limitations Our study has several limitations. First, not all patients rigorously followed regular follow-up time points, making time-dependent statistical analysis less accurate. In addition, the excessively low number of cases with 1mg DST as the endocrine remission criterion may affect the accuracy of the remission rate.Moreover, a median follow-up time of about 3 years hampered evaluation on some late complications, including cerebrovascular events and secondary brain tumor. In conclusion, our study revealed that IMRT was a highly effective second-line therapy with low side effect profile for CD patients, and it’s endocrine remission, tumor control and recurrence rates were comparable to previous reports on FRT and SRS. Data availability statement The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author. Author contributions 1. Conceptualization: FZ and HZ 2. Data curation: XL and ZX. 3. Funding acquisition: FZ. 4. Investigation: XL and ZX 5. Methodology: WW 6. Resources: XL, SS and XH 7. Validation: LL and HZ. 8. Writing – original draft: ZX 9. 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This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. *Correspondence: Fuquan Zhang, zhangfq@pumch.cn †These authors have contributed equally to this work Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. From https://www.frontiersin.org/articles/10.3389/fendo.2023.1241669/full

Highlights The most common cause of ectopic ACTH syndrome is pulmonary carcinoid tumors and squamous cell lung cancer; however it is a relatively uncommon complication of pulmonary neoplasms. The most common cause of Cushing syndrome is iatrogenic corticosteroid use and it should be considered in all patients regardless of clinical background. Low urine cortisol levels may be associated with exogenous glucocorticoid exposure. Occult glucocorticoid exposure is rare but can be evaluated with liquid chromatography. Consumers should be aware of the potential risks of taking supplements, especially those advertised as joint pain relief products. Abstract Background Well differentiated bronchial neuroendocrine neoplasms often follow a clinically indolent course and rarely cause Ectopic ACTH syndrome. Iatrogenic corticosteroid use is the most common cause of Cushing syndrome and should be considered in all patients regardless of clinical background. Case report A 59 year old woman with an 11 year history of a 1.5 cm well differentiated bronchial carcinoid, presented with Cushingoid features. Laboratory results were not consistent with an ACTH dependent Cushing Syndrome and exogenous steroids were suspected. The patient received an FDA alert regarding a glucosamine supplement she had started 4 months prior for joint pain. Discussion Ectopic ACTH production is reported in less than 5% of patients with squamous cell lung cancer and 3% of patients with lung or pancreatic (non-MEN1) neuroendocrine tumors. Factitious corticoid exposure is rare and can be evaluated with synthetic corticosteroid serum testing. Conclusion Cushing syndrome due to supplements containing unreported corticosteroid doses should be considered in patients with typical Cushingoid features and contradictory hormonal testing. 1. Introduction Well differentiated bronchial neuroendocrine neoplasms often follow a clinically indolent course and can rarely exhibit Cushing syndrome due to ectopic production of adrenocorticotropic hormone (ACTH). However the most common cause of Cushing syndrome is iatrogenic corticosteroid use and should be considered in all patients regardless of clinical background (see Fig. 1, Fig. 2, Fig. 3, Fig. 4). Download : Download high-res image (243KB) Download : Download full-size image Fig. 1. DOTATATE PET/CT demonstrates a right upper lobe pulmonary nodule with intense uptake. Download : Download high-res image (201KB) Download : Download full-size image Fig. 2. DOTATATE PET/CT demonstrates intense uptake within a right upper lobe pulmonary nodule, consistent with biopsy-proven carcinoid tumor. There are no distant sites of abnormal uptake to suggest metastatic disease. Download : Download high-res image (399KB) Download : Download full-size image Fig. 3. Artri Ajo King Supplement (Source: FDA). The label claims that the product contains glucosamine, chondroitin, collagen, vitamin C, curcumin, nettle, omega 3, and methylsulfonylmethane. Download : Download high-res image (288KB) Download : Download full-size image Fig. 4. Artri King Supplement (Source: FDA). 2. Case report A 59–year old woman with an 11 year history of a 1.5 cm well-differentiated bronchial carcinoid, presented with 20 lb. weight gain, facial swelling, flushing, lower extremity edema and shortness of breath over 3 months. On exam, the patient was normotensive, centrally obese with mild hirsutism, facial fullness and ruddiness with evidence of a dorsocervical fat pad. Initially there was concern for hormonal activation of her known bronchial carcinoid. Testing resulted in a normal 24-hour urine 5-HIAA (6 mg/d, n < 15 mg/dL), elevated chromogranin A (201 ng/mL, n < 103 ng/mL), normal histamine (<1.5 ng/mL, n < 1.7 ng mL), low-normal 7 AM serum cortisol (5.1 μg/dL, n 3.6–19.3 μg/dL), normal 7 AM ACTH (17 pg/mL, n < 46 pg/mL) and a surprisingly low 24-hr urinary free cortisol (1.8 mcg/hr, n 4.0–50.0 mcg/hr). A late night saliva cortisol was 0.03 mcg/dL (n 3.4–16.8 mcg/dL). Testosterone, IGF-1, glucose and electrolytes were appropriate. An echocardiogram showed an ejection fraction of 60% with no evidence of carcinoid heart disease. A Dotatate PET-CT was obtained to evaluate for progression of the neuro-endocrine tumor and revealed a stable right upper lobe pulmonary nodule with no evidence of metastatic disease. Given low cortisol levels, ectopic Cushing syndrome was excluded and exogenous steroids were suspected, however the patient denied use of oral,inhaled, or injected steroids. A cosyntropin stimulation study yielded a pre-stimulation cortisol 6.2 μg/dL with an adequate post-stimulation cortisol 23.5 μg/dL. At this stage of evaluation, the patient received an FDA alert regarding a glucosamine supplement she had started 4 months prior for joint pain. The notification advised of hidden drug ingredients including dexamethasone, diclofenac, and methocarbamol contained within Artri King Glucosamine supplements not listed on the product label but verified by FDA lab analysis. The FDA had received several adverse event reports including liver toxicity and even death associated with such products. The patient's symptoms gradually improved after discontinuation of the supplement. 3. Discussion 3.1. Ectopic ACTH syndrome This patient's Cushingoid features were initially suspected to be secondary to the known bronchial neuroendocrine tumor. Ectopic ACTH production accounts for about 5–10% of all Cushing Syndrome cases [1]. The most common location of ectopic ACTH is the lungs with pulmonary carcinoid tumors being the most common cause, followed by squamous cell lung cancer [2]. Despite this patient's history of bronchial carcinoid tumor and positive chromogranin histopathological marker, her laboratory results were not consistent with an ACTH dependent Cushing Syndrome. In fact, Cushing syndrome is a relatively uncommon neuroendocrine neoplasm complication. The prevalence of ectopic ACTH production in patients with lung tumors is rare, at less than 5% in squamous cell lung cancer and about 3% in patients with lung or pancreatic (non-MEN1) neuroendocrine tumors1. Patients with ACTH dependent Cushing syndrome not suspected to originate from the pituitary, undergo further testing to evaluate for an ectopic ACTH secreting tumor. These tests include conventional imaging of the chest, abdomen and pelvis, as well as functional imaging such as octreotide scans, fluoride 18-fluorodeoxyglucose-positron emission tomography [18F-FDG PET], and gallium-68 DOTATATE positron emission tomography-computed tomography [Dotatate PET-CT] scan [3]. In our literature review, we found that there was insufficient evidence to determine the sensitivity and specificity of nuclear medicine imaging techniques [4,5]. In this case, the patient had no laboratory evidence for ACTH dependent Cushing Syndrome, but given the known bronchial carcinoid tumor, a repeat Dotatate PET-CT scan was obtained which demonstrated no indication of growth or spread of the known bronchial tumor. 3.2. Supplement induced Cushing Syndrome One of the most remarkable findings in this case was the patient's low urine cortisol level in the setting of her overt Cushingoid features. In our survey of the literature, we found that low urine cortisol levels were associated with exogenous glucocorticoid use [6,7]. The low urine cortisol levels may be reflective of intermittent glucocorticoid exposure. Indeed, this patient's Cushingoid features were determined to be secondary to prolonged use of Artri King supplement. Occult glucocorticoid use is difficult to diagnose even after performing a thorough medication reconciliation as patients may unknowingly consume unregulated doses of glucocorticoids in seemingly harmless supplements and medications. The incidence of supplement induced Cushing Syndrome is currently unknown as supplements are not regularly tested to detect hidden glucocorticoid doses. Additionally, the likelihood of developing supplement induced Cushing syndrome is dependent on dosage and duration of use. In our literature review we found nine published articles describing supplement induced Cushing Syndrome [[7], [8], [9], [10], [11], [12], [13], [14], [15]], one case report of tainted counterfeit medication causing Cushing Syndrome [16], and two cases of substances with probable glucocorticoid-like activity [17,18]. Of the nine published articles of supplement induced Cushing Syndrome, six were associated with supplements marketed as arthritic joint pain relief products including ArtriKing, Maajun, and AtriVid [[7], [8], [9], [10], [11], [12]]. These products later received government issued warnings in Mexico, Malaysia, and Colombia respectively [[19], [20], [21]]. To our knowledge there have been four published reports of ArtiKing supplement induced Cushing Syndrome [[7], [8], [9], [10]]. The first documented cases were reported in 2021 in Vera Cruz, Mexico; since then the Mexican medical community reported seeing a disproportionate increase in cases of iatrogenic Cushing Syndrome due to these supplements [7]. There have also been three American published articles describing a total of 4 cases of ArtriKing supplement induced Cushing syndrome [[8], [9], [10]]. In January 2022 the FDA issued a warning about Atri Ajo King containing diclofenac, which was not listed in the product label [22]. In April 2022 the FDA expanded its warning, advising consumers to avoid all Artri and Ortiga products after the FDA found these products contained dexamethasone and diclofenac [23]. In October 2022 the FDA issued warning letters to Amazon, Walmart, and Latin Foods market for distributing Artri and Ortiga products [24]. Many supplements are not regulated by the government and may contain hidden ingredients such as glucocorticoids. In these cases further evaluation of suspected products [25], medications [16], and patient serum [26] and urine [6] utilizing techniques such as liquid chromatography may be used to confirm occult glucocorticoid exposure. This case highlights the importance of educating patients to exercise caution when purchasing health products both online and abroad. Consumers should be aware of the potential risks of taking supplements, especially those advertised as joint pain relief products. 4. Conclusion Although the most common cause of ectopic ACTH syndrome is pulmonary carcinoid tumors and squamous cell lung cancer, it is a relatively uncommon complication of pulmonary neoplasms. Exogenous Cushing syndrome due to supplements containing unreported corticosteroid doses should be considered in patients with typical Cushingoid features and contradictory hormonal testing. Occult glucocorticoid exposure is rare but can be evaluated with liquid chromatography. This case report emphasizes the importance of teaching patients to be vigilant and appropriately research their health supplements. Patient consent Formal informed consent was obtained from the patient for publication of this case report. Declaration of competing interest The authors (Tomas Morales and Shanika Samarasinghe) of this case report declare that they have no financial conflicts of interest. Shanika Samrasinghe is an editorial member of the Journal of Clinical and Translational Endocrinology: Case Reports, and declares that she was not involved in the peer review and editorial decision making process for the publishing of this article. References [1] A.R. Hayes, A.B. Grossman The ectopic adrenocorticotropic hormone syndrome: rarely easy, always challenging Endocrinol Metab Clin N Am, 47 (2) (2018 Jun), pp. 409-425, 10.1016/j.ecl.2018.01.005 PMID: 29754641 View PDFView articleView in ScopusGoogle Scholar [2] A.M. Isidori, A. 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Abstract Background 18Fluorine-Fluoro-deoxy-glucose (18F-FDG) positron emission tomography (PET) is widely used for diagnosing various malignant tumors and evaluating metabolic activities. Although the usefulness of 18F-FDG PET has been reported in several endocrine diseases, studies on pituitary disease are extremely limited. To evaluate whether dexamethasone (DEX) suppression can improve 18F-FDG PET for the localization of adrenocorticotropic hormone-secreting adenomas in the pituitary gland in Cushing’s disease (CD). Methods We included 22 patients with CD who underwent PET imaging before and after DEX administration. We compared the success rates of PET before and after DEX suppression, magnetic resonance imaging (MRI), and bilateral inferior petrosal sinus sampling (BIPSS). We determined the final locations of adenomas based on intraoperative multiple-staged resection and tumor tissue identification using frozen sections. Standardized uptake value (SUV) were analyzed to confirm the change of intensity of adenomas on PET. Results Twenty-two patients were included (age at diagnosis: 37 [13–56] years), and most were women (90.91%). Pituitary adenomas compared to normal pituitaries showed increased maximum SUV after DEX suppression but without statistical significance (1.13 versus. 1.21, z=-0.765, P = 0.444). After DEX suppression, the mean and maximum SUV of adenomas showed a positive correlation with nadir cortisol levels in high-dose DEX suppression test (Rho = 0.554, P = 0.007 and Rho = 0.503, P = 0.017, respectively). In reference sites, mean SUV of cerebellum was significantly decreased (7.65 vs. 6.40, P = 0.006*), but those of the thalamus and gray matter was increased after DEX suppression (thalamus, 8.70 vs. 11.20, P = 0.010*; gray matter, 6.25 vs. 7.95, P = 0.010*). Conclusion DEX suppression did not improve 18F-FDG PET/CT localization in patients with CD. Introduction Cushing’s disease (CD) is a rare endocrine disease that results from chronic exposure to high cortisol levels because of adrenocorticotropic hormone (ACTH)-secreting pituitary tumors and is associated with increased morbidity and mortality. It represents approximately 80% of all cases of endogenous hypercortisolism [1,2,3]. Accurate localization of primary lesions in CD leads to improved remission rates and reduced adverse events following surgery [4, 5]. A biochemical remission rate of 90–100% has been reported when tumors are localized before surgery, but it can decrease to 50–60% when surgery is performed when the location of the tumor is unknown in patients with CD [6,7,8]. Currently, magnetic resonance imaging (MRI) is the gold standard for detecting pituitary adenomas. Nevertheless, modern MRI modalities, including dynamic or volumetric sequences, can reliably detect corticotrophic adenomas in 50–90% cases of CD [9,10,11,12]. This indicates that complementary imaging strategies are required to improve the localization of primary lesions in CD. One of the most characteristic features of corticotrophic adenomas is a compromised response to negative glucocorticoid feedback, which defines glucocorticoid resistance [13]. ACTH activates the adrenal glands to synthesize and secrete cortisol, which in turn negatively modulates the release of ACTH from the pituitary gland and corticotrophin-releasing hormone (CRH) and vasopressin from the hypothalamus [1]. In CD, a corticotrophic tumor is only partially sensitive to the inhibitory feedback exerted by cortisol, which in turn is not regulating its own production and secretion of ACTH, resulting in both excessive ACTH and cortisol levels. Glucocorticoid resistance is caused by multiple factors including glucocorticoid receptor availability, splice variant expression and affinity, and imbalanced glucocorticoid receptor signaling [14, 15]. Radioactive 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) often demonstrates increased fluorodeoxyglucose (FDG) uptake in nonfunctioning and hormone-secreting pituitary adenomas [16,17,18]. In large observational studies of whole-body 18F-FDG positron emission tomography (PET) scans, incidental sellar 18F-FDG uptake was found in < 1% of cases, and this sign is highly specific for pituitary adenomas [19,20,21]. 18F-FDG PET imaging can detect up to 40% of corticotropinomas, some as small as 3 mm, and the rate of PET detection of corticotropinomas can be increased by CRH stimulation [9, 22]. Here, we evaluated whether DEX suppression could improve the localization of ACTH-secreting adenomas using 18F-FDG PET/CT in patients with CD. The rationale for this is as follows. FDG uptake of corticotrophic adenomas is less suppressed than that of normal pituitary glands after DEX suppression due to glucocorticosteroid resistance. Materials and methods Study design and population In this retrospective cohort study, we enrolled all patients with CD who underwent two rounds of 18F-FDG-PET/CT before and after 8-mg DEX suppression and pituitary MRI before surgery. Total 22 patients were included in this study, of which thirteen had bilateral inferior petrosal sinus sampling (BIPSS) results. All patients were diagnosed with CD by staff of the Department of Endocrinology and/or Neurosurgery at Severance Hospital between 2014 and 2015. The diagnosis of CD was confirmed based on biochemical test results, including the cortisol, 24-hour urine free cortisol (24 h UFC), and serum ACTH levels, overnight dexamethasone suppression test (ON DST) results, and high-dose dexamethasone suppression test (HD DST) results. Immediate remission was defined as hypocortisolism (serum cortisol level < 1.8 µg/dL) within the first 7 days after surgery. Delayed remission was defined as the achievement of hypocortisolism within 6 months, although immediate remission was not confirmed. If patients showed elevated postoperative cortisol levels and needed additional treatment within 6 months after surgery, we defined them as having persistent disease [23,24,25]. A serum cortisol concentration > 1.8 µg/dL for 8 h in the morning after 1 mg of DEX was given at midnight was considered to be a positive result in the ON DST [26]. Suppression of the serum cortisol level by > 50% for 6 h after 2 mg of DEX was administered for 2 days was defined as the suppression on the HD DST [26]. The final diagnosis was confirmed using surgical pathology and clinical follow-up. Endocrinological evaluation All laboratory analyses were performed at the Department of Laboratory Medicine, Severance Hospital. Preoperative cortisol and 24 h UFC were measured by chemiluminescence immunoassay using an automated UniCel DXC880i Synchron analyzer (Beckman Coulter, Pasadena, CA, USA; coefficient of variation [CV] ± 15 nmol/L at < 100 nmol/L and ± 15% at > 100 nmol/L). Preoperative ACTH levels were analyzed by electrochemiluminescence immunoassay using the Roche Cobas 6000 analyzer (Roche Diagnostics GmbH, Mannheim, Germany; CV ± 2.0 pmol/L at < 20 pmol/L and ± 10% at > 20 pmol/L). The serum cortisol concentration at 8:00 am the following day after 1 mg of DEX was administered at midnight was considered positive on the ON DST. We determined the result as “suppression” by the cortisol level of < 1.8 µg/dL. A serum cortisol level suppressed by > 50% of the original level after 6 hourly administrations of 2 mg of DEX for 48 h was defined as suppression on the HD DST [27]. 18F-FDG PET/CT evaluation PET/CT was performed using a GEADVANCE PET scanner (GE, Milwaukee, WI, USA) after the intravenous injection of 7–9 mCi of 18F-FDG. All patients fasted for at least 6 h before the test. Emission scanning was continued for 15 min (4.25-mm axial spatial resolution, 4.8-mm transaxial spatial resolution). Transmission scans were performed for 8 min using triple Ge-68 rod sources to correct attenuation. Gathered data were reconstructed in a 128 × 128 × 35 matrix with a pixel size of 1.95 × 1.95 × 4.25 mm by means of a filtered back-projection algorithm employing a transaxial 8.5-mm Hanning filter and 8.5-mm axial ramp filter. Two specialists independently interpreted the encoded baseline PET images, and after a two-week period, they interpreted the encoded post DEX suppression PET images. Each specialist was blinded to MRI imaging, clinical characteristics, and surgical outcomes of these subjects. Each was tasked with determining whether the PET image indicated a “negative” or “positive” result for pituitary adenoma and its location on a high-resolution computer screen. The scan after DEX suppression was performed 24 h after the oral administration of 8 mg of DEX using the same procedures as for the baseline PET/CT scan. 18F-FDG uptake analysis The Region of interest (ROI) was drawn using MIM software (version 6.5, Software INc., Cleveland, OH, USA) (Fig. 1). PET images were reviewed by experienced by an experienced specialist. The pituitary gland was identified and a circular ROI was drawn. A fixed ROI with a 3-mm diameter was used for all patients. The ROI was placed on the lesion with the highest FDG uptake. If there was no significantly increased FDG uptake, the same sized circular ROI was drawn on the suspected adenoma location. For the normal pituitary gland, the same sized 3 mm ROI was used. Fig. 1 Images of ROI for pituitary adenoma on18F-FDG PET scan Example of ROI definition in pituitary adenomas of 18F-FDG PET scan of the patients with CD. We draw the fixed circular ROI with a 3-mm diameter for pituitary adenomas (red circle) and normal pituitary gland (green circle) ROI, Reason of interest; 18F-FDG PET, 18 F-fluorodeoxyglucose positron emission tomography; CD, Cushing disease Full size image The mean standardized uptake value (SUVmean) and maximum SUV (SUVmax) for pituitary adenomas and normal pituitary glands were automatically measured using MIM, version 6.5 (Software Inc., Cleveland, OH, USA). The standardized uptake value (SUV) of the volume of interest was calculated as follows: (decoy-corrected activity (kBq) / volume (mL)) / (injected dose (kBq) / body weight (g)). SUVmean and SUVmax of pituitary adenomas were divided into the SUVmean of normal pituitary glands for adjustment. We used the ratio of SUVmax to SUVmean to analyze the homogeneity of the pituitary adenomas. MRI evaluation All patients underwent pituitary MRI with a 3.0-Tesla scanner (Achieva, Philips Medical Systems, Best, the Netherlands). Imaging protocols included T1-weighted imaging, T2-weighted imaging, and delayed gadolinium-enhanced T1-weighted imaging. The extent, location, and sizes of the pituitary tumors were reviewed based on official records determined by radiologists. Pituitary tumors were classified based on radiological findings using MRI of the sellar and parasellar regions. Type I refers to tumors < 1 cm in diameter limited to the sella. Type II tumors extend into the suprasellar space, < 1 cm from the diaphragm. Type III includes tumors extending into the suprasellar space > 1 cm from the diaphragm or sphenoid sinus and encroaching on the internal carotid arteries. Lastly, type IV refers to adenomas with obvious invasion into the cavernous sinus, as shown on MRI, and into the medial dural wall of the cavernous sinus, as confirmed during surgery. BIPSS Before surgery, BIPSS was performed to confirm the cause of CD and lateralize the tumors. A catheter was placed in patients using a unilateral femoral venous approach and 3 cc of blood was collected from the peripheral (P) and both inferior petrosal sinuses (IPS) [28]. CRH at a dose of 1 µg/kg was administered, and peripheral and petrosal samples were drawn after 5 and 10 min, respectively. The catheters and sheath were removed, and the groin was compressed under pressure until venous hemostasis was achieved. The IPS:P prolactin ratio was calculated at each time point to confirm the accuracy of the inferior petrosal venous sampling. A value of ≥1.8 was considered successful IPS catheterization. The prolactin-normalized ACTH ratio was calculated by dividing the dominant ACTH IPS:P ratio by the concurrent and ipsilateral IPS:P prolactin ratio. A value of ≥1.3 was considered diagnostic of CD. An intersinus ACTH ratio of ≥1.4 either at baseline or after stimulation was used for lateralization of the pituitary adenoma [29]. Location of the adenoma The final assignment of the true location of the pituitary adenoma was based on intraoperative multiple stage resection and tumor tissue identification using frozen sections. Surgically identified adenomas were histologically evaluated and stained for ACTH immunoreactivity. In cases of multiple specimens obtained during the procedure, the true location of the adenoma was assigned based on the original site of the specimen containing the adenoma [30]. Statistical analysis Data are presented as medians (ranges) or numbers (percentages). The baseline characteristics of the patients were compared using Kruskal–Wallis’ test with Dunn’s procedure for nonparametric continuous variables. Categorical variables were compared using Fisher’s exact test. Spearman’s correlation coefficients were used to determine the correlation between FDG uptake and hormone levels. Wilcoxon’s signed-rank test was used to identify changes in the SUV after DEX administration. The interobserver agreement for image analysis was assessed using κ statistics. κ values were categorized as follows: κ < 0.20 indicated poor agreement, κ of 0.21–0.40 indicated fair agreement, κ of 0.41–0.60 indicated moderate agreement, κ of 0.61–0.80 indicated good agreement, and κ > 0.81 indicated excellent agreement [31]. Statistical significance was set at a two-sided P < 0.05. All statistical analyses were performed using SPSS software (IBM Corp., Armonk, NY, USA). Results Patient characteristics We enrolled all patients with CD who underwent two rounds of the 18F-FDG PET/CT with or without DEX suppression and sellar MRI before transsphenoidal adenectomy (TSA). Twenty-two patients were included (age at diagnosis: 37 [13–56] years), and most were women (90.91%). Patients’ baseline characteristics are shown in Table 1. There were 16 microadenomas and 6 macroadenomas. Immediate remission was achieved in 81.82% of the patients and delayed remission in 13.64%; one patient showed persistent disease after TSA. The median preoperative 24 h UFC, serum ACTH, and cortisol levels were 443.35 (93.00–4452.00) µg/day, 36.16 (6.00–92.00) pg/mL, and 18.55 (6.00–40.00) µg/dL. The size of pituitary adenomas on MRI was 7.85 (2.00–28.00) mm. The Ki-67 index of 47.06% of adenomas ranged from 1 to 2, that of 35.29% was below 1, and that of 17.65% was 2 or higher. Overall, 75.00% of the adenomas were classified as Knosp grade 0, 5.00% as grade 1, 5.00% as grade 3b, and 15.00% as grade 4. In total, 77.27% (17/22) of patients had an ACTH-staining adenoma. Only one patient showed unsuppressed cortisol levels on the HD DST. Table 1 Patients’ imaging and clinical characteristics Full size table MRI negative but PET positive case Two patients showed negative MRI results, and one of them showed FDG uptakes on both 18F-FDG PET scans at baseline and after DEX suppression. A 26-year-old man visited our hospital complaining of weight gain and was diagnosed with ACTH-dependent CD. Cortisol secretion was suppressed on the HD DST; however, sellar MRI did not reveal any suspicious lesions. BIPSS revealed a central tumor (central/peripheral ACTH level of 36.25 after CRH stimulation) lateralized to the right side of the pituitary gland. The patient underwent 18F-FDG-PET/CT before and after DEX suppression to identify the primary lesions. Baseline PET/CT showed diffused FDG uptake with an SUVmax of 1.03 at the pituitary fossa but failed to localize the tumor. After DEX treatment, focal FDG uptake with an SUVmax of 1.06 remained at the right side of the pituitary fossa, which resulted in the successful localization of the corticotrophic adenoma. The MRI and PET/CT images of this case are presented in Fig. 2A–C. During TSA, the surgeon identified solid tumor-like tissues on the right side of the pituitary gland and successfully removed them. Results of pathology and ACTH immunohistochemistry were negative, but the patient achieved immediate biochemical remission and CD-related symptoms were relieved after surgery. We followed the patient for 98 months after the surgery and confirmed that he had lived without recurrence. Fig. 2 Images of a corticotroph with negative MRI but positive18 F-FDG PET/CT after DEX suppression An MRI-negative adenoma was detected on 18F-FDG PET/CT at baseline and after DEX suppression. In this patient, the pituitary adenoma was visible on PET scans at baseline (B) and after DEX suppression (C) at the same location, as confirmed by the surgeon A. Co-registered baseline 18F-FDG PET/CT and MRI images. Diffuse 18F-FDG uptake is detected in the pituitary fossa with an SUVmean of 0.86 and SUVmax of 1.03, but there was failure to localize the adenoma on baseline 18F-FDG PET/CT. B. Co-registered 18F-FDG PET/CT and MRI images after DEX suppression. 18F-FDG uptake is not suppressed in the right side of the pituitary gland with an SUVmean of 1.03 and SUVmax of 1.06. 18F-FDG PET/CT after DEX suppression was successful in localizing the right-sided corticotrophic adenoma C. MRI image. There is no suspicious lesion in the pituitary gland ACTH, adrenocorticotropic hormone; MRI, magnetic resonance imaging; 18F-FDG, 18 F-fluorodeoxyglucose; PET/CT, positron emission tomography/computed tomography; DEX, dexamethasone; SUVmean, mean standardized uptake value; SUVmax, maximum standardized uptake value Full size image Change of 18F-FDG uptake after DEX suppression We included 18 pituitary adenomas that were successfully localized using PET/CT after DEX suppression, and analyzed the change of SUV for 15 adenomas, excluding outliers with SUV over 2.00. The results are presented in Fig. 3A and B. The SUVmean of adenomas did not changed after DEX suppression compared to normal pituitary glands (SUVmean of adenoma/SUVmean of normal pituitary glands: 1.13 [0.85–1.35] vs. 1.14 [0.87–1.39], z=-1.288, P = 0.198). DEX suppression increased SUVmax of adenomas compared to normal pituitary glands but without statistical significance (SUVmax of adenoma/SUVmean of normal pituitary glands: 1.13 [0.96–1.52] vs. 1.21 [0.97–1.56], z=-0.765, P = 0.444). Fig. 3 Changes in the SUVs of corticotrophs between18F-FDG PET/CT before and after DEX suppression The SUVmean (A) and SUVmax (B) of corticotrophic adenomas are shown in this pairwise analysis. The SUVmean did not changed after DEX suppression from (z=-1.288, P = 0.198). The SUVmax of the corticotrophic adenoma increased from 1.13 to 1.21 (z=-0.765, P = 0.444). In this analysis, the SUVmean and SUVmax of pituitary adenomas were adjusted using the SUVmean of the normal pituitary gland. Colored plots and bars presented median and interquartile range in this figure. We presented the tumors with size larger than 5 mm and SUV adjusted by normal pituitary>1 for blue line SUVmean, mean standardized uptake value; SUVmax, maximum standardized uptake value; DEX, dexamethasone; 18F-FDG, 18 F-fluorodeoxyglucose; PET/CT, positron emission tomography/computed tomography Full size image In Fig. 3, the blue line indicates change in SUV of adenomas larger than 5 mm with higher FDG uptake than the surrounding pituitary parenchyma. For these adenomas, DEX suppression did not change the SUV (SUVmean of adenoma/SUVmean of normal pituitary glands: 1.31 [1.04–2.52] vs. 1.33 [1.05–2.38], z=-0.784, P = 0.433; SUVmax of adenoma/SUVmean of normal pituitary glands: 1.36 [1.02–2.61] vs. 1.40 [1.03–2.65], z=-1.022, P = 0.307). The value of SUV increased in 73.33% adenomas, while the SUVmax increased in 66.67% compared with normal pituitary glands after DEX treatment. Correlation between the hormone level and 18F-FDG uptake Table 2 shows the results of the Spearman correlation analysis of the SUV with preoperative cortisol, ACTH, and nadir cortisol levels on the HD DST. On the baseline 18F-FDG PET scan, the SUVmax of the adenomas did not show any correlation with the levels of three hormones. The SUVmean of adenomas showed a positive correlation with nadir cortisol levels on the HD DST (P = 0.014) and preoperative ACTH levels, with marginal significance (P = 0.062). After DEX suppression, the SUVmax and SUVmean of adenomas had a positive correlation with moderate degrees of nadir cortisol on the HD DST (SUVmax: Spearman Rho = 503, P = 0.017; SUVmean: Spearman Rho = 0.554, P = 0.007). Table 2 Correlation between FDG uptakes and hormone levels Full size table FDG uptake of reference sites after DEX suppression We evaluated the FDG uptake for five types of reference areas (normal pituitary gland, cerebellum, thalamus, white matter, and gray matter) (Table 3). Normal pituitary gland and white matter did not affect the unadjusted SUVmean by DEX suppression (all P >0.05). DEX significantly increased SUVmean of the thalamus and gray matter (thalamus, 8.70 [4.40–22.70] vs. 11.20 [6.40–17.5], P = 0.010*; gray matter, 6.25 [2.50–15.00] vs. 7.95 [5.00–11.90], P = 0.010*). However, SUVmean of the cerebellum significantly decreased after DEX administration (7.65 [4.50–10.80] vs. 6.40 [2.60–12.00], P = 0.006*). Table 3 The change of FDG uptake for reference sites after DEX suppression in the patients with CD Full size table Qualitative analysis by diagnostic modalities for CD The qualitative results of localizing pituitary adenomas in CD patients are shown in Table 4 and Fig. 4. Only 13 patients had BIPSS results. The success rates were 90.91% for MRI and 84.62% for BIPSS. Table 4 Qualitative analysis by diagnostic modalities for CD Full size table Fig. 4 Images for corticotroph adenomas that appear different for localization in18F-FDG PET/CT. 9 mm sized adenoma in the left lateral wing of pituitary gland. It was found in the left lateral wing of the pituitary gland, showing an 18F-FDG uptake in the pituitary fossa with an SUVmean of 1.04 and SUVmax of 1.07. However, after DEX suppression, the left side of the pituitary gland did not exhibit suppressed 18F-FDG uptake, with SUVmean 1.05 SUVmax 1.14 (A). Co-registered baseline 18F-FDG PET/CT and MRI images. (B). Co-registered 18F-FDG PET/CT and MRI images after DEX suppression. (C). MRI image 2 mm pituitary adenoma was detected at the left lateral wing, showing diffuse FDG uptake in the pituitary fossa with an SUVmean of 0.86 and SUVmax of 1.04. After DEX suppression, focal FDG uptake was observed, with SUVmean 0.87 and SUVmax 0.98. (D). Co-registered baseline 18F-FDG PET/CT and MRI images. (E). Co-registered 18F-FDG PET/CT and MRI images after DEX suppression. (F). MRI image Full size image In baseline PET scans, the specialists agreed that pituitary adenomas were visible in 17 scans and not visible in 5 scans. They reached a consensus that the tumor was evident in two scans, but there was a discrepancy in their assessments of its location. After DEX suppression, pituitary adenomas showed positive results in 16 scans and negative results in 5 scans. Specialists disagreed on the presence of pituitary adenomas in one case only. Interobserver agreement for localizing adenomas was 0.872 (95%CI: 0.711, 1.033) for baseline PET/CT and 0.938 (95%CI: 0.762, 1.056) for post dexamethasone suppression PET/CT, confirming excellent interobserver agreements, and the result was judged reliable. Among the instances where both opinions agreed, there were no lesions that showed differences in visibility between scans before and after DEX administration. This meant that lesions were either consistently visible or invisible in both scenarios. Discussion We found that DEX suppression did not improve localization of ACTH-secreting pituitary adenomas using 18F-FDG PET/CT. Further, it did not significantly affect FDG uptakes in adrenocorticotrophic adenomas or normal pituitaries in patients with CD. The decision to administer 8 mg dexamethasone was based on the standard high-dose DST, which is internationally recommended for differentiating between ectopic ACTH secretion and CD [26]. This test involved comparing serum cortisol levels at 8 am before and after a single dose of 8 mg dexamethasone administered at 11 pm. Suppression of the serum cortisol level to less than 50% of the baseline value indicated a diagnosis of CD [32, 33]. Previous studies have reported that the 8-mg DST has a sensitivity of 90%, specificity of 100%, accuracy of 96.8%, positive predictive value of 100%, and negative predictive value of 95.5% [34, 35]. Our use of 8 mg dexamethasone was based on the theory that orally administering dexamethasone at this dose can effectively suppress cortisol levels in ACTH-secreting pituitary tumors. We expected that FDG uptake by corticotrophic adenomas would not decrease after DEX administration in patients with CD, and this change may improve the ability to discriminate the tumor location from surrounding tissues on 18F-FDG PET. The SUVmax of pituitary adenomas adjusted for the normal pituitary gland increased from 1.13 to 1.21. However, this change was not statistically significant, and the success rate of localizing corticotrophic adenomas using 18F-FDG PET was not significantly improved after DEX suppression. If the FDG uptake of adenomas changed lesser compared to that of surrounding normal tissues after DEX suppression, the tumor could be more easily visualized because of the difference. In addition, we attempted to evaluate FDG uptakes in other brain areas (cerebellum, thalamus, white matter, and gray matter) according to DEX administration in CD patients. SUVmean of the cerebellum decreased significantly, but that of the thalamus and gray matter increased after DEX suppression. DEX did not change FDG uptake in pituitary adenoma, normal pituitary, or white matter. In a previous study analyzing FDG PET in CD patients, researchers observed varying correlations between FDG uptake and blood cortisol concentration across different brain regions [35, 36]. Nevertheless, the examination did not include an analysis of FDG uptake in the pituitary gland. Additionally, no previous studies have explored the effects of high-dose dexamethasone suppression on brain glucose metabolism in individuals with CD. Further studies are needed to explain the change in FDG uptake after DEX administration in patients with CD. 18F-FDG PET/CT provides information regarding glucose metabolism in the brain in vivo and has been widely used to evaluate brain metabolism in clinical and research settings [37]. Here, the nadir cortisol level on the HD DST correlated with the SUVmean and SUVmax of pituitary adenomas on PET scans after DEX suppression. Cortisol secretion activity is thought to be associated with metabolic activity, and DEX administration altered this. Cortisol levels and FDG uptake in other regions of the brain are correlated in patients with CD, but the correlation between cortisol and FDG uptake in the pituitary glands and/or corticotrophic adenomas themselves has not been discussed [35, 36]. In our study, cortisol levels did not show a correlation with FDG uptake of corticotrophic adenomas, but after DEX suppression FDG uptake showed a correlation with the nadir cortisol level on the HD DST. This indicated that tumors in which cortisol secretion was less suppressed by on the HD DST showed higher FDG uptake than tumors with lower cortisol levels on the HD DST. Although many studies have analyzed FDG uptake of brain tumors, reference sites defined in each study varied without a uniform standard. Gray matter, white matter, or adjacent tumor tissue was defined as a reference site [38,39,40]. We measured SUVmean of normal pituitary tissues, gray matter, white matter, thalamus, and cerebellum as possible references. We defined the SUVmean of normal pituitary tissues as a reference because the localization of adenomas requires an apparent difference between the adenoma and surrounding tissues. Use of fixed ROI to measure FDG uptake caused partial volume effect in this study. However, lesions smaller than 5 mm with intense FDG uptake may still show increased FDG uptake, especially in tumors, albeit with lower SUV values compared with the actual values [41]. This study was performed because pituitary adenomas smaller than 5 mm with higher FDG uptake than the surrounding pituitary parenchyma have been observed in routine clinical practice. To control for the partial volume effect, the analysis was performed again for tumors which were larger than 5 mm and had higher FDG uptake than the surrounding pituitary parenchyma, and the results remained unchanged. PET/CT has been explored as an alternative to or combined with MRI for the localization of corticotrophic adenomas. 18F-FDG PET/CT has a limited role in CD diagnosis, but CRH stimulation can increase its success rate [22, 42]. This study is important for increasing the effectiveness of PET using DEX. In addition, data on DEX effect on brain metabolism in patients with CD will be important for future studies. Conclusions DEX suppression did not improve the localization of 18F-FDG PET/CT in patients with CD. This is considered to have sufficient significance in an effort to increase the diagnostic value of 18F-FDG PET/CT. Data Availability All datasets generated and/or analyzed during the current study are not publicly available but are available from the corresponding author upon reasonable request. Abbreviations 18F-FDG: 18F-fluorodeoxyglucose PET/CT: Positron emission tomography/computed tomography DEX: Dexamethasone MRI: Magnetic resonance imaging BIPSS: Bilateral inferior petrosal sinus sampling CD: Cushing’s disease SUV: Standardized uptake value ACTH: Adrenocorticotropic hormone CRH: Corticotrophin-releasing hormone FDG: Fluorodeoxyglucose 24hr UFC: 24-hour urine free cortisol ON DST: Overnight dexamethasone suppression test HD DST: High-dose dexamethasone suppression test SUVmean : Mean standardized uptake value SUVmax : Maximum standardized uptake value P: Peripheral IPS: Inferior petrosal sinuses TSA: Transsphenoidal adenectomy References Newell-Price J, Bertagna X, Grossman AB, Nieman LK. Cushing’s syndrome. The Lancet. 2006;367:1605–17. Article CAS Google Scholar Steffensen C, Bak AM, Rubeck KZ, Jørgensen JOL. Epidemiology of Cushing’s syndrome. Neuroendocrinology. 2010;92:1–5. Article CAS PubMed Google Scholar Lacroix A, Feelders RA, Stratakis CA, Nieman LK. 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Author information Authors and Affiliations Endocrinology, Institute of Endocrine Research, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea Kyungwon Kim, Cheol Ryong Ku & Eun Jig Lee Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea Dong Kyu Kim Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea Ju Hyung Moon, Eui Hyun Kim & Sun Ho Kim Contributions Conception and design: EJL, CRK, KK. Acquisition of data: KK, DKK. Analysis and interpretation of data: KK. Drafting the article: KK. Administrative/technical/material support: JHM, EHK, SHK. Study supervision: EJL, CRK. Writing, review, and revision of the manuscript: KK, DKK, SHK, CRK. Final approval of the manuscript: CRK, EJL. Corresponding authors Correspondence to Cheol Ryong Ku or Eun Jig Lee. Ethics declarations Ethics approval and consent to participate The data were collected under the conditions of regular clinical care with approval from the ethics committee of our hospital, and the requirement for written informed consent was waived owing to its retrospective design (institutional review board number: 2023-0110-001). Consent for publication Not applicable. Competing interests The authors declare no conflicts of interest that could be perceived as prejudicing the impartiality of this study. Additional information Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Electronic supplementary material Additional file 1 of Dexamethasone suppression for 18F-FDG PET/CT to localize ACTH-secreting pituitary tumors Additional file 1 Supplementary Material 1 Below is the link to the electronic supplementary material. 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The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Reprints and Permissions Cite this article Kim, K., Kim, D.K., Moon, J.H. et al. Dexamethasone suppression for 18F-FDG PET/CT to localize ACTH-secreting pituitary tumors. Cancer Imaging 23, 85 (2023). https://doi.org/10.1186/s40644-023-00600-8 Download citation Received09 May 2023 Accepted08 August 2023 Published12 September 2023 DOIhttps://doi.org/10.1186/s40644-023-00600-8 Share this article Anyone you share the following link with will be able to read this content: Get shareable link Provided by the Springer Nature SharedIt content-sharing initiative Keywords 18F-FDG PET/CT ACTH-secreting pituitary tumor Cushing’s disease Dexamethasone suppression High-dose dexamethasone suppression test From https://cancerimagingjournal.biomedcentral.com/articles/10.1186/s40644-023-00600-8

Introduction: The differential diagnosis between Cushing’s disease (CD) and ectopic ACTH syndrome (EAS) is complex, and bilateral inferior petrosal sinus sampling (BIPSS) is considered the gold-standard test. However, BIPSS with corticotropin-releasing hormone (CRH) stimulation is rarely available. Objective: This retrospective cohort study aimed to assess the accuracy of the inferior petrosal sinus to peripheral ACTH gradient (IPS:P) before and after desmopressin stimulation for the differential diagnosis of ACTH-dependent Cushing’s syndrome (CS), applying different cutoff values. Methods: A total of 50 patients (48 with CD and 2 with EAS) who underwent BIPSS were included in this study. The sensitivity and specificity of IPS:P in BIPSS before and after desmopressin stimulation were evaluated. Various cutoff values for IPS:P were examined to determine their diagnostic accuracy. Results: Using the traditional IPS:P cutoff, the sensitivity was 85.1% before stimulation, 89.6% after stimulation, and a combined sensitivity of 91.7%. Applying cutoff values of IPS:P >1.4 before and >2.8 after stimulation, the sensitivity was 87.2% and 89.6%, respectively, with a combined sensitivity of 91.7%. Receiver operating characteristic (ROC) curve analysis determined optimal cutoff values of 1.2 before stimulation and 1.57 after stimulation, resulting in a sensitivity of 93.6% and 93.8%, respectively, with a combined sensitivity of 97.9%. Specificity remained at 100% throughout all analyses. Among the 43 patients who responded positively to stimulation, 42 (97.7%) did so within the first three minutes, and all 43 (100%) did so within the first five minutes. None of the assessed clinical variables predicted the ACTH response to stimulation in BIPSS with statistical significance. Discussion: ACTH stimulation with desmopressin during BIPSS improves the accuracy of IPS:P, making it a valuable tool for investigating ACTH-dependent Cushing’s syndrome. Considering the low risk of complications, we recommend the use of desmopressin stimulation during BIPSS for the differential diagnosis of ACTH-dependent CS. Introduction Cushing Syndrome (CS) is a rare disease that results from chronic exposure to elevated cortisol levels. It can be caused by either endogenous or exogenous factors, and its incidence is estimated to be 0.7-3.2 cases per million per year (1, 2). The mortality rate for CS is elevated and may remain higher than the general population even after remission of hypercortisolism (3, 4). The causes of endogenous CS are traditionally classified into two categories: ACTH-dependent (about 80-85% of cases) and ACTH-independent (15-20% of cases) (5). The most common cause of ACTH-dependent CS (75-80% of cases) is Cushing Disease (CD), which is characterized by a corticotropic pituitary adenoma. The remaining cases (15-20%) of ACTH-dependent CS are caused by ectopic ACTH syndrome (EAS), which occurs when tumors of various sites, histological differentiation, and aggressiveness produce ACTH. There are also exceptionally rare cases (<1%) of ectopic CRH-producing tumors (5, 6). CS diagnosis is a complex and challenging pathway due to the variable pattern of hormonal findings, the non-specificity of clinical presentation, particularly in mild hypercortisolism states (7), and the technical limitations of diagnostic tests. Once CS is confirmed, it should be differentiated between ACTH-dependent or -independent cases (8). ACTH levels <10 pg/ml suggest an adrenal cause; ACTH levels >20 pg/ml suggest ACTH-dependent causes; and levels between 10-20 pg/ml are considered indeterminate, requiring additional tests to establish the etiology (5, 8). When ACTH-dependency is confirmed, the next diagnostic step is the differentiation between CD and EAS. In this step, non-invasive tests are initially recommended, such as the CRH test (CRH-t), the 8 mg dexamethasone suppression test (DST-8 mg), and a pituitary magnetic resonance imaging (MRI) (5, 8). These tests, however, presents heterogenous results, depend on the availability of CRH, restricted in many countries including Brazil, and present low discriminatory power (9, 10). An alternative to CRH-t is the use of desmopressin, which stimulates ACTH release in most patients harboring ACTH-secreting pituitary adenomas. The use of this stimulus for the differential diagnosis of CD vs EAS is controversial, since studies have demonstrated that EAS patients may present ACTH elevation following desmopressin administration (11–14). The DST-8 mg is widely available; however it also presents limitation due to the variability of criteria used; furthermore, it has shown insufficient discriminatory capacity in some studies (15, 16). Pituitary MRI fails to detect adenomas in CD patients in about 30-50% of cases even with modern technology equipment (17); moreover, it may also generate false-positive results since pituitary incidentalomas are common in the population, including macroadenomas (18). In cases of conflicting non-invasive test results and unavailability of other methods, bilateral inferior petrosal sinus sampling (BIPSS) should be performed to detect a central-to-peripheral ACTH gradient that allows the localization of the ACTH production (5). Some authors and guidelines recommend performing BIPSS in all patients with pituitary lesions < 6 mm demonstrated on MRI (5, 8, 19), whereas others suggest BIPSS should routinely be performed, especially to guide surgical therapy of CD (20–23). Thus, the procedure is considered the gold-standard in the differential diagnosis of ACTH-dependent CS, preferentially performed with CRH or, less frequently, with desmopressin. The use of CRH is a limiting factor since it is unavailable in many countries. On the other hand, although used in some medical centers, desmopressin as a stimulus for BIPSS is still poorly debated and assessed in the literature, and its utility in this setting remains uncertain since studies validating it in different populations and in larger series are still lacking (8, 24–26). A recent study evaluating desmopressin in a large cohort of patients proposed new diagnostic criteria, questioning the need of stimulus with the new cut-offs (27). Thus, the aim of this study is to assess the role of central-to-peripheral ACTH gradient after stimulus with desmopressin during BIPSS for the differential diagnosis of ACTH-dependent CS in a cohort of patients followed-up in a referral center for CS in Brazil. Patients and methods Patients Between 1998 and 2020, 107 patients with ACTH-dependent CS were retrospectively evaluated at the Neuroendocrinology clinic of a tertiary center in Southern Brazil for BIPSS under desmopressin stimulation during initial diagnostic evaluation or after recurrence. Of these, 58 patients underwent BIPSS with desmopressin, 50 of which for the initial diagnostic evaluation, 7 after recurrence and 1 after emergency adrenalectomy. Eight patients who underwent BIPSS were excluded for insufficient data regarding final etiologic diagnosis (lack of histopatological confirmation, lack of biochemical remission 6 months after surgery, or lack of remission after radiotherapy). Finally, 50 patients were included in the analysis. The present study was conducted in compliance with the principles laid down in the Declaration of Helsinki and was approved by the Hospital de Clínicas de Porto Alegre Ethics Committee. Diagnosis of CS and ACTH-dependency status After exhaustive screening for exogenous glucocorticoid administration, CS diagnosis was based on the presence of at least two of the following conditions: cortisol after low-dose dexamethasone suppression test (either 1 mg overnight or 0.5 mg 6/6 hours for 48h) > 1.8 µg/dL (DST-1mg); 24-h urinary free cortisol (UFC) or late night salivary cortisol consistently elevated in at least two samples (8). Additionally, late night serum cortisol > 7.5 µg/dL (8) and a desmopressin test (DES-t) with a peak ACTH > 71.8 pg/mL or an increase in ACTH ≥ 37 pg/mL from baseline (28) were also considered suggestive of CS. After clinical and biochemical diagnostic confirmation of CS, plasma ACTH measurement classified CS into ACTH-dependent (ACTH > 20 pg/dL) or ACTH-independent (ACTH < 10 pg/dL). Values between 10-20 pg/dL were considered indeterminate and new samples were obtained for correct classification (8). Next, patients diagnosed with ACTH-dependent CS underwent pituitary MRI for the identification of an adenoma. Due to the unavailability of CRH-t, it was rarely performed. The DES-t for the differential diagnosis of CD and EAS was considered predictive of CD when the increase was > 20% in cortisol or >35% in ACTH after stimulus. In virtue of its low accuracy, DST-8 mg was only performed in a few cases. Patients with inconclusive or negative imaging, those with adenomas < 6 mm or those with adenomas > 6 mm but discordant non-invasive tests were submitted to BIPSS with sampling of ACTH at baseline and after desmopressin stimulus. After investigation, patients with a suggestive diagnosis of CD underwent transsphenoidal surgery. Histological confirmation of a pituitary adenoma staining positive for ACTH was considered the gold-standard for diagnosis. Additionally, patients with inconclusive or absent histological specimen who exhibited clinical and biochemical remission 6 months after surgery or who remitted after pituitary radiotherapy were also considered diagnosed for CD. The EAS cases were confirmed based on surgical excision or biopsy of tumoral lesions confirming the presence of ACTH-staining neoplastic cells. Bilateral inferior petrosal sinus sampling The procedure was performed in the presence of documented hypercortisolism, in an angiography room, under sedation with fentanyl and midazolam, and by a qualified professional in interventional radiology. Initially, bilateral common femoral venipuncture was performed, maintained with 6 French (F) introducers. Then, ascending catheterization of the superior vena cava and internal jugular veins was performed with a 5F vertebral catheter and hydrophilic guidewire, with final positioning of the catheter tip at the level of the inferior petrosal sinuses. Angiographic confirmation was performed after injection of 10 ml of diluted nonionic contrast under digital subtraction, demonstrating bilateral sinus and sellar region opacification. In situations of fine-caliber inferior petrosal sinuses, a coaxial microcatheter was used for a better distal reach of the required topography. Heparinization was not usually necessary in this technique, only sequential washing of the catheters was performed between the sampling times with saline solution with 2 ml of heparin for each 1000 ml of solution. Samples were collected after washing the catheters at baseline. Then, 10 µg of desmopressin was administered intravenously and samples were collected after one, three, five, and 15 minutes. In some cases, the sampling times were slightly different, but always with one sampling at baseline and at least 3 samplings after stimulation. All samples were collected in ice-cold tubes, kept on ice and then centrifuged in a refrigerated centrifuge and frozen at -8°C until ACTH measurement, which occurred immediately after the end of the procedure. After the samplings, the catheters and introducers were removed, followed by manual compression of the inguinal region at the puncture site for 10 minutes, until complete hemostasis. After compression, a compressive dressing was placed at the puncture site and the patients remained at bed rest without flexing the thigh for 6 h. Our routine protocol in performing the BIPSS did not include the concomitant measurement of prolactin as suggested in some previous studies in the literature. Hormone assays Until April 2004, cortisol was measured using a commercially available radioimmunoassay (RIA) kit (Diagnostic Systems Laboratories, Webster, TX, USA). From May 2004 to March 2010, the method was modified to an electrochemiluminescence immunoassay (ECLIA) kit (Modular Analytics E 170; Roche, Mannheim, Germany). From March 2010 to February 2014, cortisol was measured by chemiluminescence immunoassay (ADVIA Centaur XP Immunoassay System, Tarrytown, NY, USA). From February 2014 to October 2019, the method was Competitive Electrochemiluminescence. (Roche e602 equipment line). From October 2019 until the end of the study, the method was Microparticle Chemiluminescent Immunoassay. (Abbott equipment line). ACTH measurements up to February 2000 were performed by commercially available RIA. From February 2000 to April 2015, the method was chemiluminescence with the Immulite 1000 equipment. From May 2015 to April 2018, the method was electrochemiluminescence with the Roche e602 equipment. From May 2018 to August 2019, the method was sandwich electrochemiluminescence using the Roche e602 equipment. From August 2019 until the end of the study, the method was chemiluminescent immunoassay in the Immulite 2000 equipment. These assay differences do not show a large variation from normal values and as samples collected from the same patient were always analyzed with the same assay, the calculations of different indexes of central versus peripheral samplings did not change as a result of the trials. Of the cases studied, ACTH was measured by RIA in 1 patient, by Immulite 1000 in 35 patients, by Roche e602 via electrochemiluminescence in 9 patients, by Roche e602 via sandwich electrochemiluminescence in 4 patients and by Immulite 2000 in 1 patient. The basal ACTH and UFC values, therefore, are presented according to the percentage above the ULN according to each methodology used at each moment. For the calculation of the ACTH inferior petrosal sinus to peripheral gradient (IPS:P), however, absolute values were used since the ratios are calculated for the same patient using the same assay. Statistical analysis The Kolmogorov-Smirnov test was used to assess the distribution of variables. Continuous variables with normal distribution are presented as mean ± standard deviation (SD). Continuous variables with asymmetric distribution are shown as median and interquartile range (IQR). Categorical variables were compared using Fischer’s exact test. The comparison of continuous variables was performed using the Mann-Whitney test. ROC curves were used to assess the ability of the IPS:P gradient to discriminate between CD and EAS, and the Youden index was used to define optimal cutoffs. Sensitivity and specificity were calculated for the different criteria analyzed. Statistical analyzes were performed using the SPSS 24.0 program (statistical package software, SPSS Incorporation, Chicago, IL, USA). Differences were considered significant when p<0.05. Results Patient characteristics are shown in Table 1. During the study period, 50 patients with a confirmed diagnosis of ACTH-dependent CS whose etiology could be confirmed through histopathological or biochemical data (remission after 6 months of surgery or after radiotherapy) who had undergone the BIPSS were included. The mean age (SD) at diagnosis was 38.22 (15.56) years, 39 patients (78%) were female, and 48 patients had CD and 2 EAS. Table 1 Table 1 Characteristics of studied patients. In the imaging results, 23 (46%) were microadenomas, among which 15 were < 0.6cm (65.2% of microadenomas), 8 were macroadenomas (16%), and 19 had negative or inconclusive imaging (38%). One of the patients with EAS had an image suggestive of a 0.4 cm microadenoma on MRI. Regarding macroadenomas, the indication for BIPSS was proposed based on the following situations: 3 presented with a clinical picture of EAS, including 2 with systemic lesions suspicious for neoplasia, 3 presented imaging characteristics that were somewhat atypical for adenomas, 1 was associated with a brainstem vascular lesion and one was a recurrent disease with postsurgical alteration and residual lesion. BIPSS was performed in 44 patients who had not yet undergone investigation or treatment and in 6 patients who had been previously treated for CD but had relapsed during follow-up. No complications were recorded in any of the cases submitted to BIPSS. There were no thromboembolism events related to the procedure. At baseline (before stimulation), 49 patients were evaluated (1 patient with CD had samples collected, but his results were not properly recorded). The median IPS:P gradient at baseline was 6.62 (IQR 2.46-11.36) in patients with CD and 1.14 (IQR 1.10-1.14) in patients with EAS (p=0.01). Using the IPS:P>2 gradient criteria, 40 of 47 patients with CD were positive and none of the 2 patients with EAS were positive, resulting in 85.1% sensitivity (95% confidence interval (CI) 71.1-93.3%) and 100% specificity. After stimulation with desmopressin, all 50 patients were evaluated. The median SPI:P gradient after stimulation was 29.46 (IQR 15.39-61.50) in patients with CD and 1.26 (min-max 1.25-1.28) in patients with EAS (p=0.01). In patients with EAS, the highest ACTH peak was 537 pg/mL (109.5% increase from baseline), while in patients with CD, the lowest increase from baseline was 19.48%. Using the IPS:P gradient criteria > 3, 43 of 48 patients with CD were positive, and none of the 2 patients with EAS were positive, resulting in 89.6% sensitivity (95%CI 76.5-96.1%) and 100% specificity. When evaluating patients who were positive at baseline and/or after stimulation in a combined manner, 44 of 48 CD patients were positive, whereas no EAS patients were positive. The overall sensitivity, therefore, was 91.7% (95%CI 79.1-97.3%), and the specificity was 100%. Of the 9 negative patients at baseline, 3 (33.33%) became positive after stimulation. Among the 43 patients who tested positive after the stimulus, 42 (97.7%) had already tested positive up to the third minute, and 100% of the patients were positive up to the fifth minute (Figure 1), totaling 86% of the total sample. Of the 3 patients whose stimulation was necessary, 2 had microadenomas and 1 had macroadenomas. In the two patients with EAS, the time of peak of ACTH was at 1 minute for patient 1 (31.1% increase from baseline) and at 3 minutes for patient 2 (109.5% increase from baseline). Figure 1 Figure 1 Time (minutes) until obtaining IPS:P gradient values of ACTH considered positive response of BIPSS after stimulation with desmopressin. When assessing only the 23 patients with microadenoma, 20 of 22 patients with CD were positive at baseline, and the patient with EAS and 0.4 cm microadenoma was negative, resulting in 90.9% sensitivity (95%CI 69.37-98.4%), while maintaining 100% specificity. After stimulation, all 22 patients with CD were positive and the only patient with EAS and microadenoma was negative, resulting in 100% sensitivity (95%CI 81.5-100%) while maintaining 100% specificity. When only microadenomas < 0.6 cm were evaluated, 12 of 14 CD patients were positive at baseline, and the patient with EAS and 0.4 cm microadenoma was negative, resulting in 85.7% sensitivity (95%CI 56.2-97.5), with 100% specificity. After stimulation, all 14 patients with CD were positive, and the patient with EAS and microadenoma was negative, resulting in a sensitivity of 100% (95%CI 73.2-100%) while maintaining 100% specificity. All eight patients with microadenomas >0.6cm were already positive at baseline and remained positive after stimulation (100% sensitivity and 100% specificity). Thus, only patients with microadenoma <0.6 cm improved sensitivity after stimulation. Among the 8 patients with macroadenoma, sensitivity was 75% at baseline and remained the same after stimulation. However, when assessed for need for stimulation, only one patient with macroadenoma benefited, but sensitivity did not increase because a patient who was positive at baseline became negative after stimulation. Assessing all patients with positive imaging on MRI (micro or macroadenomas, n = 31), 26 of 30 CD patients were positive at baseline, and the patient with EAS and microadenoma was negative, resulting in 86.7% sensitivity and 100% specificity. After stimulation, 28 of 30 CD patients were positive and the patient with EAS and microadenoma remained negative, resulting in 93.3% sensitivity and maintaining 100% specificity. The combined sensitivity (baseline or after stimulus) in this group of patients was 96.7%. Among the 19 patients with negative imaging, 18 had baseline results and were evaluated. Baseline sensitivity was 82.4%. After stimulation, data from 19 patients were evaluated and resulted in a sensitivity of 83.3%. When the patients with negative imaging (n=19) and those with microadenomas <0.6 cm (n=15) were analyzed together, which represent the most difficult cases in clinical practice, we observed that the IPS:P gradient >2 at baseline resulted in sensitivity of 83.9% and 100% specificity. After stimulation, the IPS:P >3 gradient had a sensitivity of 90.6% while maintaining 100% specificity. After assessing the traditionally proposed criteria, the analysis was performed using the criteria proposed by Chen et al. (27). Using the IPS:P gradient at baseline > 1.4, 41 of 47 CD patients were positive and none of the EAS patients were positive, resulting in 87.2% sensitivity (95%CI 73.5-94.7%) while maintaining 100% specificity. After stimulation, using the IPS:P>2.8 gradient criteria, 43 of 48 patients with CD were positive, resulting in 89.6% sensitivity (95%CI 76.5-96.1%), strictly the same as the traditional criteria maintaining 100% specificity. When evaluating patients who were positive at baseline and/or after stimulation, 44 of 48 patients with CD were positive, and no patient with EAS was positive, resulting in 91.7% overall sensitivity (95%CI 79.1-97.3%), the same as the traditional criteria. Finally, only 2 of 49 patients who were negative at baseline became positive after stimulation. To establish institution-specific cut-off points, a ROC curve was performed to assess the accuracy of the central/peripheral ACTH gradient in BIPSS in our cohort of patients. For the IPS:P gradient at baseline, the cut-off point with the highest accuracy was 1.2, whereas for the IPS:P gradient after stimulation, the cut-off point with the highest accuracy was 1.57 (Figure 2). Using these cut-off points, 44 of 47 CD patients were positive at baseline and no EAS patients were positive, resulting in 93.6% sensitivity (95%CI 81.4-98.3%), while maintaining 100% specificity. After stimulation, 45 of 48 CD patients were positive and no EAS patients were positive, resulting in 93.8% sensitivity (95%CI 81.8-98.4%), with 100% specificity (Figure 3). When evaluating patients who were positive at baseline and/or after stimulation, 47 of 48 CD patients were positive and no EAS patients were positive, resulting in an overall sensitivity of 97.9% (95%CI 87.5-99.9%) With 100% specificity. Finally, only 2 patients who were negative at baseline became positive after stimulation. Figure 2 Figure 2 ROC curve of baseline IPS:P values in BIPSS in the investigation of ACTH-dependent CS. Figure 3 Figure 3 ROC curve of IPS:P values after stimulation with desmopressin in BIPSS in the investigation of ACTH-dependent CS. In the comparison between the traditional criterion and our study criterion, the baseline sensitivity changed from 85.1 to 93.6%. After stimulation, baseline sensitivity changed from 89.6 to 93.8%, respectively. A summary of the sensitivity results with the different diagnostic criteria is presented in Table 2. Table 2 Table 2 Sensitivity of BIPSS with traditional criteria and with present study criteria. Technical difficulties or anatomical variations were found in 6 patients undergoing BIPSS. Among the 43 cases with a positive IPS:P gradient, 3 had anatomical variations and 1 had some technical difficulty. Of the 5 cases in which the IPS:P gradient did not occur (false-negatives), 1 presented anatomical variation and 1 presented some technical difficulty during the test. Among the 6 patients who underwent BIPSS after recurrence, all had a final diagnosis of CD, and only 1 was negative on BIPSS. Of the 50 patients evaluated, 43 had undergone DES-t as part of the diagnostic workup, of which 41 were later diagnosed with CD and 2 with EAS. Forty patients were considered responsive in DES-t, 38 patients with CD and 2 patients with EAS. Among the 40 responsive patients, 34 (85%) were also positive in BIPSS, all with a final diagnosis of CD. The 3 non-responsive patients in DES-t presented a positive response in BIPSS after desmopressin. Of the 6 patients who were positive in DES-t but negative in BIPSS, 2 were patients with EAS. Of the 4 patients with CD, 2 had normal petrosal sinus anatomy, 1 had a report of some anatomical variation, and 1 had a report of technical difficulties during BIPSS. Thus, DES-t was not able to predict response to desmopressin during BIPSS (p>0.9999). When comparing the ACTH values at baseline, 3, 5 and 10 minutes after stimulation in BIPSS, there was no significant difference between the group with positive versus negative DES-t, as well as no difference in the time to positivity between the groups, adenoma size, and number of patients with negative imaging. In addition, the clinical variables evaluated (ACTH, UFC, DST-1mg, baseline cortisol, adenoma size) were not able to significantly predict response to stimulus. Discussion In this study, the use of BIPSS with ACTH measurements at baseline and after stimulation with desmopressin in the differential diagnosis of the ACTH-producing source in a sample of 50 patients with ACTH-dependent CS and inconclusive non-invasive tests resulted in 85.1% baseline sensitivity, increasing to 89.6% after stimulation, maintaining 100% specificity when applying traditional IPS:P≥2 criteria at baseline and ≥3 after stimulation (29). When combined, the baseline and/or stimulated sensitivity results were 91.7%. Results of meta-analyses that combined studies performed with CRH stimulation and desmopressin indicate that the sensitivity of BIPSS ranges from 86-97% and the specificity from 89-100% (27, 30). Published studies with desmopressin are generally small, with a variable number of cases of EAS, different indications for BIPSS, and variable diagnostic criteria. In a study with a sample of 56 patients with ACTH-dependent CS and negative imaging, using the criterion of IPS:P≥2 at baseline and IPS:P≥3 after stimulation with desmopressin, the combined sensitivity was 92.1% and 100% specificity, similar to the findings of the present study (25). Smaller studies that also used desmopressin stimulation found similar (26, 31–33) or slightly higher sensitivities (34, 35). Studies performed exclusively in pediatric patients were less uniform, with one of them reporting similar results to studies that included adults (36) and another study demonstrating lower sensitivity in adult population (37). Our institution’s optimal cut-off points, determined by analyzing the ROC curve, were IPS:P≥1.2 at baseline and ≥1.57 after stimulation. This resulted in 93.6% baseline sensitivity (it was 85.1% with IPS:P≥2), and 93.8% after stimulation (was 89.6% with IPS:P≥3), and a combined sensitivity of 97.9% (it was 91.7%), maintaining specificity at 100%. Despite the increased sensitivity, these criteria should be used with caution, since the number of cases with EAS was small. The IPS:P gradient at baseline and after stimulation achieved in patients with EAS in some studies with desmopressin would exceed the cutoffs found by us (24, 25, 27), which would incorrectly classify these patients as CD. Before adopting the new values in our institution, therefore, more patients with EAS are necessary to validate these criteria. Also using the ROC curve, Castinetti et al. evaluated 43 patients with ACTH-dependent SC (36 DC and 7 EAS) and established the criteria of IPS:P>2 at baseline or after stimulation, obtaining a sensitivity of 86% at baseline and 97% after stimulation with desmopressin, not mentioning the combined sensitivity. The study, however, showed 85% specificity at baseline, given that a patient with EAS had a 3.33 gradient (24). In addition to applying the traditional criteria, Machado et al. also used ROC curve analysis to establish cut-off points, finding an IPS:P≥1.45 at baseline (88.2% sensitivity) and ≥ 2.04 after stimulation (92.2% sensitivity) as optimal, both with 100% specificity, although the authors did not recommend the use of these new values (25). The results of these studies using the ROC curve suggest that lower cutoff points, both at baseline and after stimulation, can improve sensitivity without compromising specificity. However, a study that performed a ROC curve in patients stimulated with CRH found an optimal 2.10 baseline cut-off, slightly higher than the traditional one of 2, although the post-stimulation cut-off point was 2.15, lower than the one usually used (38). A study with desmopressin, in turn, found values in the ROC curve of 1.76 at baseline, lower than the traditional one, but ≥3.9 after stimulation, higher than the gradient of three usually used, increasing baseline sensitivity but keeping the sensitivity after stimulation unchanged (32). The largest published study evaluating BIPSS with desmopressin stimulation evaluated 226 patients with CD and 24 with EAS (27). Applying the IPS:P>2 criteria at baseline and >3 after stimulation, the sensitivity was 87.2 and 94.2%, respectively, while maintaining 100% specificity. The combined sensitivity was 96.5%. In this series, 3 cases of EAS reached gradients greater than 2 after stimulation, which suggests that cut-off points equal to or lower than this may decrease specificity. The authors also performed an ROC curve, determining the cutoff point of >1.4 at baseline and >2.8 after stimulation. In this analysis, the sensitivity at baseline was 94.7% and 96% after stimulation, resulting in a combined 97.8% sensitivity, higher than that found with the traditional criteria. According to the authors, with these cut-off points, only 7 patients benefited from the stimulus. After this publication, no other studies have tested these new cutoffs. Our study was the first, therefore, to assess the new values. In our series, using the cutoff point of >1.4 at baseline and >2.8 after stimulation, the sensitivity was 87.2 and 89.3%, respectively, and the combined sensitivity was 91.7%, thus slightly improving the sensitivity at baseline with little change after stimulation. In an attempt to identify predictors of need for stimulation, Chen et al. found that patients requiring stimulation had adenomas < 0.6 cm or negative imaging. In addition, patients who required stimulation had lower IPS ACTH levels and did not lateralize. These data, however, are obtained only after performing the BIPSS, which makes their use in practice unfeasible (27). In our series, among patients with microadenomas, only those with lesions <0.6 cm benefited from the stimulus. Patients with negative imaging had a small increase in sensitivity. A patient with a macroadenoma also benefited from the stimulus, although the sensitivity of the cases with macroadenoma did not change, as a positive patient at baseline became negative after the stimulus. Despite current recommendations suggesting to perform BIPSS in patients with adenomas < 0.6 cm or with negative/inconclusive imaging results (8, 39), Chen et al. identified 2 patients with EAS and adenomas > 0.6 cm who would be misdiagnosed with CD if the 0.6 cm threshold were respected. Therefore, they suggest performing BIPSS in all patients with ACTH-dependent CS (27). Given the relevance of EAS cases in this study, a discussion about the current size criteria for indicating BIPSS should be undertaken. Of our 50 patients, 43 (41 CD and 2 EAS) underwent DES-t prior to BIPSS, and 40 were considered responsive, including the two cases of EAS. Among the responders, 34 patients also responded to the stimulus during the BIPSS, all of them with CD. The 3 patients who did not respond to the peripheral stimulus were, however, positive in the BIPSS. The lack of correlation between the DES-t results and the BIPSS may be related to the different sampling intervals in the two exams (short intervals in the BIPSS and long intervals in the peripheral test). Considering that the majority (86%) of our patients performed both tests, it is possible to conclude that the DES-t did not help in the prediction of response to the central stimulus, which makes the use of peripheral test results debatable for this purpose. Of the BIPSS studies with desmopressin, only one described the results of DES-t, although it did not perform any specific analysis of the relationship with BIPSS (36). The study differs from ours, also, as it only evaluated pediatric patients. Although BIPSS is still considered the gold standard in the differential diagnosis of ACTH-dependent CS, some authors have suggested that the procedure should be indicated only in cases in which t-CRH was negative (40, 41). Recent studies have evaluated non-invasive strategies combining t-CRH, DES-t, TSD-8mg, and imaging to reduce the need for BIPSS. Strategies that resulted in a positive predictive value of 100%, however, included t-CRH as part of the diagnostic process (42, 43), which makes adherence to this diagnostic modality inapplicable in many countries due to the unavailability of CRH. In one of these studies, the combination of TSD-8mg with DES-t, which would be possible in Brazil, was inferior to the combination of DES-t with t-CRH or t-CRH with TSD-8mg (43). The low number of patients undergoing TSD-8mg in our study did not allow the evaluation of this strategy. Although not recommended as a test in the differential diagnosis of the etiology of ACTH-dependent SC, DES-t seems promising as a marker of long-term postoperative outcome and as an early marker of recurrence (44), which encourages further studies in these circumstances. Despite there have been reports of thromboembolic events related to BIPSS that occurred heparin (45, 46), it is a very rare complication. The administration of desmopressin, which increases coagulation factor VIII and von Willebrand factor (47), has raised concerns about the potential for increased incidence of thromboembolic events during BIPSS. This is due to the fact that desmopressin is associated with the hypercoagulable state of CS (48) and may also interfere with VIII and von Willebrand factors. The study by Chen et al, the largest published with desmopressin to date, did not record any case of thromboembolism, even without routine anticoagulation during the procedure (27). In our study, performed without routine anticoagulation, there were also no thromboembolic events. The only desmopressin BIPSS study that recorded thromboembolic events routinely used heparin during the procedure (25). Thromboembolic events, therefore, do not appear to be an additional concern when using desmopressin, with or without the use of heparin during the procedure. The decision regarding the use or not of anticoagulants during BIPSS should be a decision of each institution and based on the usual anticoagulation recommendations. In our study, we did not perform the concomitant dosage of prolactin in samples collected from the inferior petrosal sinuses, a procedure that potentially reduces false negatives, as advised by some authors based on studies with CRH (49–51) and a study with desmopressin (31). These findings, however, were not confirmed by all groups, both with CRH (52) and with desmopressin (32), and their applicability depends on further studies to define its role. In our study, a total of 3 patients who were negative at baseline benefited from the stimulus, As they became positive, 2 of them with microadenomas and one with macroadenoma. The study by Chen et al. questions the use of routine stimulation in all patients to reduce the risks and the duration of the procedure, potentially reducing complications. The authors argue that, when using the IPS:P>1.4 criterion at baseline, the sensitivity was high enough to classify most patients, with the exception of 7 patients with adenoma <0.6 cm who needed stimulation (27). Our study, however, would have misclassified a case with CD and macroadenoma as EAS if the stimulus had not been performed. The assessment of the need for stimulation in cases of CS with macroadenoma is limited since most studies performed the BIPSS only in patients with lesions < 0.6 cm or negative imaging, preventing a more comprehensive assessment. Considering that BIPSS is currently still the gold standard in the differential diagnosis of ACTH-dependent CS, even small gains in sensitivity should be considered important since incorrect classification of patients can lead to inappropriate treatments and potentially fatal delays in the resolution of hypercortisolism. Considering that BIPSS is generally well tolerated and the rate of serious complications is low (53), other strategies to reduce the risks of the procedure that do not involve avoiding the stimulus seem necessary. In this context, it is important to evaluate the time interval between the infusion of the secretagogue and the positive test result. In our study, 97.7% of the patients who tested positive after stimulation were already positive in the third minute and 100% of the patients were positive until the fifth minute, demonstrating that there seems to be no benefit in prolonging the test beyond this period. All of the few studies on BIPSS with desmopressin have directly or indirectly reported a similar time to positivity and for peak ACTH (i.e., positive up to 3-5 minutes) (26, 33, 35, 37). Stimulating patients for a maximum time of 5 minutes considerably reduces the procedure time without neglecting the sensitivity gain resulting from the stimulation and may, therefore, be a strategy to potentially reduce the risk of complications. Our study evaluated a sample of patients whose BIPSS indication was more comprehensive since the unavailability of t-CRH and the low accuracy of TSD-8mg limited the use of non-invasive tests. The wide heterogeneity existing in the BIPSS studies regarding the characteristics of the evaluated patients (primary diagnosis or recurrence), the BIPSS technique (sampling times, anticoagulant use, material used, laboratory assays, cut-off points, type of secretagogue) makes direct comparisons difficult. Conducting multicenter prospective studies with a greater sample of EAS patients is necessary to improve our understanding of the best cut-off points and procedure duration. The present study has some limitations, as expected in the complexity of CS investigation. Our main limitation is that the low prevalence of EAS that underwent BIPSS, resulting from the rarity of this condition, may explain the high specificity when applying the cutoff points indicated by the ROC curve, and the application of these new gradients of IPS:P depends on validation in larger samples of EAS. Lower specificity may result from poor responsiveness to the secretagogue (desmopressin or CRH), cyclic CS during periods of normal cortisol secretion or due to anomalous venous drainage (54). Retrospective data collection and analysis prevented access to complete information for all patients. There were differences over time in terms of sampling times, although at least 3 different samplings were always performed throughout the study period. We highlight that, in this study, we did not discuss the data regarding the eventual lateralization of the basal ACTH values and after stimulation with desmopressin to guide the location of the pituitary adenoma in the transsphenoidal surgery. This utility of the BIPSS has been less and less recommended in the literature due to the imprecision of the results, especially due to the existence of venous communications between the cavernous sinuses and the instability and intensity of blood aspiration for sample collection. In conclusion, in BIPSS with ACTH dosage, the use of stimulation with desmopressin increases the sensitivity of the test from 85.1% to 89.6%, reaching 100% in the sub-analysis of microadenomas. In spite of being small, this increase is useful in the investigation of ACTH-dependent CS, a clinical situation in which gains in diagnostic sensitivity are very important. Additionally, considering the low risk of complications and the possibility to interrupt the test within 5 minutes, as demonstrated in our study, our data recommend the use of stimulation with desmopressin in the BIPSS in the differential diagnosis of ACTH-dependent CS. Data availability statement The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation. Ethics statement The studies involving human participants were reviewed and approved by Hospital de Clínicas de Porto Alegre Ethics Committee. Written informed consent to participate in this study was provided by the participants’ legal guardian/next of kin. Author contributions TA, TR and MC conceived the study and designed the research. TA conducted the data collection and database management. TA performed the data analysis. LS, MF and FG performed the BIPSS procedures. TA, TR, FC and MC contributed to the interpretation of the results. TA and MC drafted the manuscript. FC critically revised the manuscript. All authors read and approved the final version of the manuscript. All authors contributed to the article and approved the submitted version. Funding This work was supported by the Research Incentive Fund (FIPE) of Hospital de Clínicas de Porto Alegre and the Postgraduate Program in Medical Sciences: Endocrinology (PPG ENDO) from Universidade Federal do Rio Grande do Sul. Acknowledgments The authors would like to acknowledge the contributions of Guilherme Alcides Flores Soares Rollin, Arthur Boschi, and Camila Viecceli to the data collection process. Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Publisher’s note All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Abbreviations BIPSS, bilateral inferior petrosal sinus sampling; CD, Cushing Disease; CRH-t, CRH test; CS, Cushing Syndrome; DES-t, desmopressin test; DST-1 mg, 1 mg dexamethasone suppression test; DST-8 mg, 8 mg dexamethasone suppression test; EAS, Ectopic ACTH Syndrome; ECLIA, electrochemiluminescence immunoassay; F, French; IPS:P, inferior petrosal sinus to peripheral gradient; IQR, interquartile range; MRI, magnetic resonance imaging; RIA, radioimmunoassay; SD, standard deviation; UFC, urinary free cortisol; ULN, upper limit of normal. References 1. Newell-Price J, Bertagna X, Grossman AB, Nieman LK. Cushing’s syndrome. 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Second-line tests in the diagnosis of adrenocorticotropic hormone-dependent hypercortisolism. Ann Lab Med (2021) 41(6):521–31. doi: 10.3343/alm.2021.41.6.521 PubMed Abstract | CrossRef Full Text | Google Scholar Keywords: Cushing’s syndrome, Cushing’s disease, ectopic ACTH syndrome, bilateral inferior petrosal sinus sampling, ACTH, desmopressin Citation: Almeida TSd, Rodrigues TdC, Costenaro F, Scaffaro LA, Farenzena M, Gastaldo F and Czepielewski MA (2023) Enhancing Cushing’s disease diagnosis: exploring the impact of desmopressin on ACTH gradient during BIPSS. Front. Endocrinol. 14:1224001. doi: 10.3389/fendo.2023.1224001 Received: 17 May 2023; Accepted: 11 July 2023; Published: 03 August 2023. Edited by: Fabienne Langlois, Centre Hospitalier Universitaire de Sherbrooke, Canada Reviewed by: Filippo Ceccato, University of Padua, Italy Matthieu St-Jean, Université de Sherbrooke, Canada Copyright © 2023 Almeida, Rodrigues, Costenaro, Scaffaro, Farenzena, Gastaldo and Czepielewski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. *Correspondence: Tobias Skrebsky de Almeida, tsalmeid@gmail.com Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. From https://www.frontiersin.org/articles/10.3389/fendo.2023.1224001/full

Nearly one-third of women with endogenous Cushing’s syndrome and normal bone mineral density have a low trabecular bone score, according to study data. “A large proportion of patients had degraded microarchitecture despite normal BMD,” Hiya Boro, DM, MD, MBBS, consultant in endocrinology, diabetes and metabolism at Aadhar Health Institute in India, and colleagues wrote. “The risk of fracture may be underestimated if BMD alone is measured. Hence, trabecular bone score should be added as a routine complementary tool in the assessment of bone health in patients with Cushing’s syndrome.” Data were derived from Boro H, et al. Clin Endocrinol. 2023;doi:10.1111/cen.14944. Researchers conducted a cross-sectional study at a single center in India from March 2018 to August 2019. The study included 40 women with overt endogenous Cushing’s syndrome and 40 healthy sex-matched controls. Seum and salivary cortisol and plasma adrenocorticotropic hormone (ACTH) were measured. Participants were considered ACTH independent if they had a level of less than 2.2 pmol/L. Areal BMD was measured at the lumbar spine, femoral neck, total hip and distal one-third of the nondominant distal radius. Low BMD for age was defined as a z score of less than –2. Trabecular bone score was measured at the lumbar spine. Fully degraded microarchitecture was defined as a trabecular bone score of 1.2 or lower and partial degradation was a trabecular bone score of 1.21 to 1.34. Of the 40 women with Cushing’s syndrome, 32 were ACTH-dependent and the other eight were ACTH independent. Of the independent group, seven had adrenal adenoma and one had adrenocortical carcinoma. Women with Cushing’s syndrome had lower BMD at the lumbar spine (0.812 g/cm2 vs. 0.97 g/cm2; P < .001), femoral neck (0.651 g/cm2 vs. 0.773 g/cm2; P < .001) and total hip (0.799 g/cm2 vs. 0.9 g/cm2; P < .001) than the control group. “No significant difference was noted in the distal radius BMD,” the researchers wrote. “This may be explained by the fact that cortisol excess predominantly affects trabecular rather than cortical bone.” Absolute trabecular bone score was lower in the Cushing’s syndrome group compared with controls (1.2 vs. 1.361; P < .001). Based on trabecular bone score, 42.5% of women with Cushing’s syndrome had fully degraded bone microarchitecture, 45% had partially degraded microarchitecture and 12.5% had normal microarchitecture. “In our study, 32.5% of patients had normal BMD with low trabecular bone score, thus highlighting the fact that patients may have normal BMD despite degraded microarchitecture,” the researchers wrote. “As such, assessment of BMD alone may underestimate the risk of fractures in patients with Cushing’s syndrome.” From https://www.healio.com/news/endocrinology/20230809/bmd-may-underestimate-bone-deterioration-for-women-with-endogenous-cushings-syndrome

Abstract Rationale: Ectopic ACTH-producing pituitary adenoma (EAPA) of the clivus region is extraordinarily infrequent condition and merely a few reports have been reported to date. Patient concerns: The patient was a 53-year-old woman who presented with Cushing-like appearances and a soft tissue mass in the clivus region. Diagnoses: The final diagnosis of clivus region EAPA was established by clinical, radiological and histopathological findings. Interventions: The patient underwent gross total clivus tumor resection via transsphenoidal endoscopy. Outcomes: Half a year after surgery, the patient Cushing-like clinical manifestations improved significantly, and urinary free cortisol and serum adrenocorticotropin (ACTH) returned to normal. Lessons: Given the extreme scarcity of these tumors and their unique clinical presentations, it may be possible to misdiagnose and delayed treatment. Accordingly, it is especially crucial to summarize such lesions through our present case and review the literature for their precise diagnosis and the selection of optimal treatment strategies. 1. Introduction Pituitary adenoma arises from the anterior pituitary cells and is the commonest tumor of the sellar region.[1] It makes up approximately 10% to 15% of all intracranial tumors.[2] Ectopic pituitary adenoma (EPA) is defined as a pituitary adenoma that occurs outside the sellar area and has no direct connection to normal pituitary tissue.[3] The most frequent sites of EPA are the sphenoid sinus and suprasellar region, and much less frequent sites including the clivus region, cavernous sinus, and nasopharynx.[4] Hypercortisolism and the series of symptoms it leads to is termed Cushing syndrome (CS).[5] CS is classified into adrenocorticotropin (ACTH)-dependent and ACTH-independent CS depending on the cause, accounting for 80% to 85% and 15% to 20% of cases, respectively.[6] Pituitary adenoma accounts for ACTH-dependent CS 75% to 80%, while ectopic ACTH secretion accounts for the remaining 15% to 20%.[7] Ectopic CS is a very rare disorder of CS caused by an ACTH-secreting tumor outside the pituitary or adrenal gland.[8] It has been reported that ectopic ACTH-producing pituitary adenoma (EAPA) can occur in the sphenoid sinus, cavernous sinus, clivus, and suprasellar region,[9] with EAPA in the clivus region being extremely rare, and merely 6 cases have been reported in the English literature (Table 1).[10–15] Furthermore, as summarized in the Table 1, EAPA in the clivus area has unique symptoms, which may lead to misdiagnosis as well as delay in treatment. Therefore, we herein described a case of CS from an EAPA of the clivus region and reviewed relevant literature for the purpose of further understanding this extraordinarily unusual condition. Table 1 - Literature review of cases of primary clival ectopic ACTH-producing pituitary adenoma (including the current case). Reference Age (yr)/sex Symptoms Imaging findings Maximum tumor diameter (mm) Preoperative elevated hormone IHC Surgery RT Follow-up (mo) Outcome Ortiz et al 1975[10] 15/F NA NA NA NA NA Right transfrontal craniotomy, NA Yes NA Symptomatic relief Anand et al 1993[11] 58/F Anosphrasia, blurred vision, occasional left frontal headache, Routine radiographic evaluation revealed a clival tumor and nasopharyngeal mass with bone erosion. MRI demonstrated a Midline homogeneous mass. 30 ACTH ACTH in a few isolated cells Maxillotomy approach, GTR Yes 12 Symptomatic relief Pluta et al 1999[12] 20/F Cushing syndrome MRI revealed a hypodense contrast-enhancing lesion. NA ACTH ACTH Transsphenoidal surgery, GTR No 18 Symptomatic relief Shah et al 2011[13] 64/M Facial paresthesias, myalgias, decreased muscle strength, and fatigue CT imaging showed a clival mass. 21 ACTH ACTH NA, GTR No 7 Symptomatic relief Aftab et al 2021[14] 62/F Transient unilateral visual loss MRI showed a T2 heterogeneously enhancing hyperintense lesion. 21 No ACTH Transsphenoidal resection, GTR NO 6 Symptomatic relief Li et al 2023[15] 47/F Bloody nasal discharge, dizziness and headache CT revealed an ill-defined mass eroding the adjacent bone. MRI T1 showed a heterogeneous mass with hypointensity, hyperintensity on T2-weighted images and isointensity on diffusion-weighted images. 58 NA ACTH Transsphenoidal endoscopy, STR Yes 2 Symptomatic relief Current case 53/F Headache, and dizziness, Cushing syndrome CT demonstrated bone destruction and a soft tissue mass. MRI T1 revealed irregular isointense signal, and MRI T2 showed isointense signal/slightly high signal. 46 ACTH ACTH Transsphenoidal endoscopy, GTR NO 6 Symptomatic relief ACTH = adrenocorticotropin, CT = computed tomography, GTR = gross total resection, IHC = immunohistochemistry, MRI = magnetic resonance imaging, NA = not available, RT = radiotherapy, STR = subtotal resection. 2. Case presentation A 53-year-old female presented to endocrinology clinic of our hospital with headache and dizziness for 2 years and aggravated for 1 week. Her past medical history was hypertension, with blood pressure as high as 180/100 mm Hg. Her antihypertensive medications included amlodipine besylate, benazepril hydrochloride, and metoprolol tartrate, and she felt her blood pressure was well controlled. In addition, she suffered a fracture of the thoracic vertebrae 3 month ago; and bilateral rib fractures 1 month ago. Physical examination revealed that the patient presented classical Cushing-like appearances, including moon face and supraclavicular and back fat pads, and centripetal obesity (body mass index, 25.54 kg/m2) with hypertension (blood pressure, 160/85 mm Hg). Laboratory studies revealed high urinary free cortisol levels at 962.16 µg/24 hours (reference range, 50–437 µg/24 hours) and absence of circadian cortisol rhythm (F [0am] 33.14 µg/dL, F [8am] 33.52 µg/dL, F [4pm] 33.3 µg/dL). ACTH levels were elevated at 90.8 pg/mL (reference range, <46 pg/mL). The patient low-dose dexamethasone suppression test demonstrated the existence of endogenous hypercortisolism. High-dose dexamethasone suppression test results revealed that serum cortisol levels were suppressed by <50%, suggesting the possibility of ectopic ACTH-dependent CS. Serum luteinizing hormone and serum follicle stimulating hormone were at low levels, <0.07 IU/L (reference range, 15.9–54.0 IU/L) and 2.57 IU/L (reference range, 23.0–116.3 IU/L), respectively. Insulin-like growth factor-1, growth hormone (GH), prolactin (PRL), thyroid stimulating hormone, testosterone, progesterone and estradiol test results are all normal. Oral glucose tolerance test showed fasting glucose of 6.3 mmol/L and 2-hour glucose of 18.72 mmol/L; glycosylated hemoglobin (HbA1c) was 7.1%. Serum potassium fluctuated in the range of 3.14 to 3.38 mmol/L (reference range, 3.5–5.5 mmol/L), indicating mild hypokalemia. High-resolution computed tomography (CT) scan of the sinuses revealed osteolytic bone destruction of the occipital clivus and a soft tissue mass measuring 20 mm × 30 mm × 46 mm (Fig. 1A). The mass filled the bilateral sphenoid sinuses and involved the cavernous sinuses, but the pituitary was normal. Cranial MR scan showed the T1W1 isointense signal and the T2W1 isointense signal/slightly high signal in the sphenoid sinus and saddle area (Fig. 1B–D). Bone density test indicated osteoporosis. Figure 1.: Radiological findings. (A) CT demonstrated bone destruction and a soft tissue mass on the occipital clivus (white arrow). (B) Axial view of the MR T1 revealed irregular isointense signal in the sphenoid sinus and saddle area (white arrow). (C and D) Axial view and sagittal view of the MR T2 showed isointense signal/slightly high signal in the sphenoid sinus and saddle area (black arrow). CT = computed tomography. Subsequently, the patient underwent gross total clivus tumor resection via transsphenoidal endoscopy. During surgery, the tumor was found to be light red in color with a medium texture, and the tumor tissue protruded into the sphenoidal sinus cavity and eroded the clival area. Histologically, the tumor cells were nested, with interstitially rich blood sinuses and organoid arrangement (Fig. 2A). The tumor cells were relatively uniform in size, with light red cytoplasm, delicate pepper salt-like chromatin, and visible nucleoli (Fig. 2B). In addition, mitosis of tumor cells was extremely rare. Immunohistochemically, the neoplasm cells were diffuse positive for CK (Fig. 2C), CgA (Fig. 2D), ACTH (Fig. 2E), Syn and CAM5.2, with low Ki-67 labeling index (<1%) (Fig. 2F). Simultaneously, all other pituitary hormone markers like GH, thyroid stimulating hormone, PRL, luteinizing hormone, as well as follicle stimulating hormone were negatively expressed. On the basis of these medically historical, clinical, laboratorial, morphologic, and immunohistochemical findings, the final pathological diagnosis of an EAPA was established. Figure 2.: HE and immunohistochemical findings. (A) Histologic sections revealed morphologically homogeneous tumor cells in nests with a prominent and delicate vascularized stroma (H&E, × 200). (B) The tumor cells had fine chromatin with visible nuclei and rare mitoses (H&E, × 400). CK (C), CgA (D) and ACTH (E) immunohistochemically showed diffuse reactivity of the tumor cells (SP × 200). (F) The proliferation index is <1% on Ki-67 staining (SP × 200). When evaluated 2 months after surgery, her Cushing-like characteristics had well improved, and her blood pressure was normal. Furthermore, her serum cortisol and ACTH returned to the normal levels. Six-month postoperative follow-up revealed that serum cortisol and ACTH were stable at normal levels, and no signs of tumor recurrence were detected on imaging. 3. Discussion EAPA is defined as an ACTH-secreting ectopic adenoma located outside the ventricles, and has no continuity with the normal intrasellar pituitary gland.[9] ACTH promotes cortisol secretion by stimulating the adrenal cortical fasciculus. The clinical manifestations of hypercortisolism are diverse, and the severity is partly related to the duration of the cortisol increase.[8] Clival tumors are typically uncommon, accounting for 1% of all intracranial tumors. There are many differential diagnoses for clival lesions, including the most common chordoma (40%), meningioma, chondrosarcoma, astrocytoma, craniopharyngioma, germ cell tumors, non-Hodgkin lymphoma, melanoma, metastatic carcinoma, and rarely pituitary adenoma.[16] The commonest clival EPA is a PRL adenoma, followed by null cell adenoma, and the least common are ACTH adenoma and GH adenoma.[2] The clival EAPA is extremely unwonted, and only 6 other cases apart from ours have been reported in literature so far (Table 1). The average age of the patients with these tumors was 48 years (range, 15–64 years). There was a obvious female predominance with a female-to-male prevalence ratio of 6:1. Only 2 patients (2/6, 33.3%) with reported clinical symptoms, including our patients, presented with overt clinical manifestations of CS. Compression of the mass on adjacent structures (e.g., nerves) may result in anosphrasia, visual impairment, headache, myalgias, decreased muscle strength, dizziness and facial sensory abnormalities. The diagnosis and localization of these tumors relied heavily on radiological imaging. Head MRI was the most basic method used for them detection, for localization adenomas and their invasion of surrounding structures to guide the choice of treatment and surgical options methods. Radiographic characteristics had been reported in 6 patients with EAPA in the clivus region. All of these patients (6/6, 100%) had initial positive findings of sellar MRI (or CT) identifying an ectopic adenoma before surgery. MR T1 was usually a low-intensity or isointense signal, while MR T2 was usually an isointense or slightly higher signal. The maximum diameter of the tumor was reported in 5 cases, with the mean maximum diameter was 35.2 mm (range, 21–55 mm) according to preoperative MRI and intraoperative observations. As summarized in Table 1, 4/5 clival EAPA cases secreted ACTH. Histologically, all cases (6/6, 100%) expressed ACTH scatteredly or diffusely. The gold standard for the treatment of CS caused by EAPA was the surgical removal of EPA, which was essential to achieve remission and histological confirmation of the disease.[9] The most common method of EAPA resection in the clivus region was transsphenoidal sinus resection (4/6, 66.67%), followed by craniotomy (1/6, 16.67%) and maxillary osteotomy (1/6, 16.67%). Transsphenoidal endoscopic surgery allowed resection of the EAPA and manipulation of neurovascular structures and avoidance of cerebral atrophy, whereas craniotomy allowed full exposure of the suprasellar region, direct visualization or manipulation of the adenoma, and reduced the risk of postoperative CSF leak.[9] Both approaches had their advantages, and there was no consensus on which surgical approach was best for the treatment of EAPA in the slope area.[9] The choice of the best surgical approach was believed to be based on the condition of the adenoma, as well as the general condition of the patient and the experience of the surgeon.[9] As summarized in Table 1, most complete tumor resections were achieved regardless of the method chosen. A minority of patients underwent postoperative radiotherapy (3/7, 42.86%), and most of them had invasion of the surrounding bone tissue. All patients experienced effective postoperative relief of symptoms. In summary, due to the rarity of this disorder, an accurate preoperative diagnosis of EAPA in the slope area is extremely challenging for the clinician or radiologist. The final precise diagnosis relies on a combination of clinical symptoms, imaging findings, histology and immunohistochemical markers. For this type of tumor, surgery is an effective treatment to relieve the clinical manifestations caused by tumor compression or hormonal secretion. The choice of postoperative adjuvant radiotherapy is mainly based on the presence of invasion of the surrounding bone tissue. Further cases may be necessary to summarize the clinical features of such lesions and to develop optimal treatment strategies. Acknowledgments We would like to thank the patient and her family. Author contributions Conceptualization: Yutao He. Data curation: Ziyi Tang. Formal analysis: Na Tang. Methodology: Yu Lu, Fangfang Niu, Jiao Ye, Zheng Zhang, Chenghong Fang. Writing – original draft: Yutao He. Writing – review & editing: Yutao He, Lei Yao. Abbreviations: ACTH adrenocorticotropin CS cushing syndrome CT computed tomography EAPA ectopic ACTH-producing pituitary adenoma EPA ectopic pituitary adenoma GH growth hormone PRL prolactin References [1]. Gittleman H, Ostrom QT, Farah PD, et al. Descriptive epidemiology of pituitary tumors in the United States, 2004-2009. J Neurosurg. 2014;121:527–35. Cited Here | PubMed | CrossRef | Google Scholar [2]. Karras CL, Abecassis IJ, Abecassis ZA, et al. Clival ectopic pituitary adenoma mimicking a Chordoma: case report and review of the literature. Case Rep Neurol Med. 2016;2016:8371697. Cited Here | Google Scholar [3]. Bălaşa AF, Chinezu R, Teleanu DM, et al. Ectopic intracavernous corticotroph microadenoma: case report of an extremely rare pathology. Rom J Morphol Embryol. 2017;58:1447–51. Cited Here | Google Scholar [4]. Zhu J, Wang Z, Zhang Y, et al. Ectopic pituitary adenomas: clinical features, diagnostic challenges and management. 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Cushing syndrome caused by ectopic adrenocorticotropic hormone-secreting pituitary adenomas: case report and literature review. World Neurosurg. 2020;142:75–86. Cited Here | Google Scholar [10]. Ortiz-Suarez H, Erickson DL. Pituitary adenomas of adolescents. J Neurosurg. 1975;43:437–9. Cited Here | PubMed | CrossRef | Google Scholar [11]. Anand VK, Osborne CM, Harkey HL. Infiltrative clival pituitary adenoma of ectopic origin. Otolaryngol Head Neck Surg. 1993;108:178–83. Cited Here | PubMed | CrossRef | Google Scholar [12]. Pluta RM, Nieman L, Doppman JL, et al. Extrapituitary parasellar microadenoma in Cushing’s disease. J Clin Endocrinol Metab. 1999;84:2912–23. Cited Here | View Full Text | PubMed | CrossRef | Google Scholar [13]. Shah R, Schniederjan M, DelGaudio JM, et al. Visual vignette.s Ectopic ACTH-secreting pituitary adenoma. Endocr Pract. 2011;17:966. Cited Here | Google Scholar [14]. Aftab HB, Gunay C, Dermesropian R, et al. “An Unexpected Pit” - ectopic pituitary adenoma. J Endocr Soc. 2021;5:A557–8. Cited Here | Google Scholar [15]. Li Y, Zhu JG, Li QQ, et al. Ectopic invasive ACTH-secreting pituitary adenoma mimicking chordoma: a case report and literature review. BMC Neurol. 2023;23:81. Cited Here | Google Scholar [16]. Wong K, Raisanen J, Taylor SL, et al. Pituitary adenoma as an unsuspected clival tumor. Am J Surg Pathol. 1995;19:900–3. Cited Here | View Full Text | PubMed | CrossRef | Google Scholar Hide full references list Keywords: clivus region; Cushing; Ectopic ACTH; like appearance; producing pituitary adenoma From https://journals.lww.com/md-journal/Fulltext/2023/06230/Cushing_syndrome_caused_by_an_ectopic.32.aspx

Abstract Background The diagnosis of Cushing’s syndrome is challenging; however, through the clinical picture and the search for secondary causes of osteoporosis, it was possible to reach the diagnosis of the case reported. There was an independent, symptomatic ACTH hypercortisolism manifested by typical phenotypic changes, severe secondary osteoporosis and arterial hypertension in a young patient. Case presentation A 20-year-old Brazilian man with low back pain for 8 months. Radiographs showed fragility fractures in the thoracolumbar spine, and bone densitometry showed osteoporosis, especially when evaluating the Z Score (− 5.6 in the lumbar spine). On physical examination, there were wide violaceous streaks on the upper limbs and abdomen, plethora and fat increase in the temporal facial region, hump, ecchymosis on limbs, hypotrophy of arms and thighs, central obesity and kyphoscoliosis. His blood pressure was 150 × 90 mmHg. Cortisol after 1 mg of dexamethasone (24.1 µg/dL) and after Liddle 1 (28 µg/dL) were not suppressed, despite normal cortisoluria. Tomography showed bilateral adrenal nodules with more severe characteristics. Unfortunately, through the catheterization of adrenal veins, it was not possible to differentiate the nodules due to the achievement of cortisol levels that exceeded the upper limit of the dilution method. Among the hypotheses for the differential diagnosis of bilateral adrenal hyperplasia are primary bilateral macronodular adrenal hyperplasia, McCune–Albright syndrome and isolated bilateral primary pigmented nodular hyperplasia or associated with Carney’s complex. In this case, primary pigmented nodular hyperplasia or carcinoma became important etiological hypotheses when comparing the epidemiology in a young man and the clinical-laboratory-imaging findings of the differential diagnoses. After 6 months of drug inhibition of steroidogenesis, blood pressure control and anti-osteoporotic therapy, the levels and deleterious metabolic effects of hypercortisolism, which could also impair adrenalectomy in the short and long term, were reduced. Left adrenalectomy was chosen, given the possibility of malignancy in a young patient and to avoid unnecessary definitive surgical adrenal insufficiency if the adrenalectomy was bilateral. Anatomopathology of the left gland revealed expansion of the zona fasciculate with multiple nonencapsulated nodules. Conclusion The early identification of Cushing’s syndrome, with measures based on the assessment of risks and benefits, remains the best way to prevent its progression and reduce the morbidity of the condition. Despite the unavailability of genetic analysis for a precise etiological definition, it is possible to take efficient measures to avoid future damage. Peer Review reports Background Cushing’s syndrome may be exogenous or endogenous and, in this case, can be ACTH-dependent or independent. In the case reported, there was an independent, symptomatic ACTH hypercortisolism manifested by typical phenotypic changes, severe secondary osteoporosis and arterial hypertension in a young patient. Osteoporosis secondary to hypercortisolism occurs due to chronic reduction in bone formation, loss of osteocytes and increased reabsorption caused by intense binding of cortisol to glucocorticoid receptors present in bone cells [1]. In addition, excess cortisol impairs vitamin D metabolism and reduces endogenous parathyroid hormone secretion, intestinal calcium reabsorption, growth hormone release, and lean body mass [2]. Subclinical Cushing disease occurs in up to 11% of individuals diagnosed with early-onset osteoporosis and 0.5–1% of hypertension patients. [3] A cross-sectional study published in 2023 revealed a prevalence of 81.5% bone loss in 19 patients with Cushing’s syndrome [2]. The prevalence of osteopenia ranges from 60 to 80%, and the prevalence of osteoporosis ranges from 30 to 65% in patients with Cushing’s syndrome. Additionally, the incidence of fragility fractures ranges from 30 to 50% in these patients [4] and is considered the main cause of morbidity affecting the quality of life. The diagnosis is challenging, given the presence of confounding factors; however, through the clinical picture and the search for secondary causes of osteoporosis, it was possible to reach a syndromic diagnosis. Early identification of this syndrome, with measures based on the assessment of risks and benefits, remains the best way to prevent progression and reduce morbidity related to this disease [2]. Case presentation A 20-year-old Brazilian male patient reported low back pain that had evolved for 8 months, with no related trauma. He sought emergency care and performed spinal radiographs on this occasion (03/2019). Due to the several alterations observed in the images, he was referred to the Orthopedics Service of the Hospital of Federal University of Juiz de Fora, which prescribed orthopedic braces, indicated physical therapy and was referred again to the Osteometabolic Diseases outpatient clinic of the Endocrinology and Rheumatology Services of the Hospital of Federal University of Juiz de Fora on 10/2019. The radiographs showed a marked reduction in the density of bone structures, scoliotic deviation with convexity toward the left and reduction in the height of the lumbar vertebrae, with partial collapses of the vertebral bodies at the level of T12, L1, L2, L3 and L5, with recent collapses in T12 and L1, suggesting bone fragility fractures. The same can be seen in posterior magnetic resonance imaging (Fig. 1). Fig. 1 Radiography and Magnetic Resonance Imaging (MRI) of lumbosacral spine in profile Full size image Bone scintigraphy on 08/2019 did not reveal hyper flow or anomalous hyperemia in the topography of the thoracolumbar spine, and in the later images of the exam, there was a greater relative uptake of the tracer in the lumbar spine (vertebrae T10–T12, L2–L4), of nonspecific aspect, questioning the presence of osteoarticular processes or ankylosing spondylitis. It was also observed in the bone densitometry requested in October 2019, performed by dual-energy X-ray absorptiometry (DXA), low bone mineral density (BMD) in the lumbar spine, femoral neck and total femur, when comparing the results to evaluating the Z Score (Table 1). Table 1 Dual-energy X-ray absorptiometry (DXA) Full size table Thus, the diagnosis of osteoporosis was established, and treatment with vitamin D 7000 IU per week was started due to vitamin D3 insufficiency associated with the bisphosphonate alendronate 70 mg, also weekly. The patient had a past pathological history of fully treated syphilis (2018) and perianal condyloma with a surgical resection on 09/2017 and 02/2018. In the family history, it was reported that a maternal uncle died of systemic sclerosis. In the social context, the young person denied drinking alcohol and previous or current smoking. On physical examination, there were no lentiginous skin areas or blue nevi; however, wide violet streaks were observed on the upper limbs and abdomen, with plethora and increased fat in the temporal facial region and hump (Fig. 2a, b), limb ecchymosis, hypotrophy of the arms and thighs, central obesity and kyphoscoliosis. Systemic blood pressure (sitting) was 150 × 90 mmHg, BMI was 26.09 kg/m2, and waist circumference was 99 cm, with no reported reduction in height, maintained at 1.55 m. Fig. 2 Changes in the physical examination. a Violet streaks on the upper limbs, b Violet streaks on abdomen Full size image An investigation of secondary causes for osteoporosis was initiated, with the following laboratory test results (Table 2). Table 2 Laboratory tests Full size table Computed tomography of the abdomen with adrenal protocol performed on 08/13/2020 characterized isodense nodular formation in the body of the left adrenal and in the lateral portion of the right adrenal, measuring 1.5 cm and 0.6 cm, respectively. The lesions had attenuation of approximately 30 HU, showing enhancement by intravenous contrast, with an indeterminate washout pattern in the late phase after contrast (< 60%) (Fig. 3). Fig. 3 Computed tomography abdomen with adrenal protocol Full size image After contact with the interventional radiology of the Hospital of Federal University of Juiz de Fora, catheterization of adrenal veins was performed on 10/2020; however, it was not possible to perform adequate lesion characterization due to obtaining serum cortisol levels that extrapolated the dilutional upper limit of the method (Table 3). Table 3 Adrenal catheterization Full size table The calculation of the selectivity index was 6.63 (Reference Value (RV) > 3), confirming the good positioning of the catheter within the vessels during the procedure. The calculated lateralization index was 1.1296 (VR < 3), denoting bilateral hormone production. However, as aldosterone was not collected from a peripheral vein, it was not possible to obtain the contralateral rate and define whether there was contralateral suppression of aldosterone production [5]. Due to pending diagnoses for a better therapeutic decision and Cushing’s syndrome in clear evolution and causing organic damage, it was decided, after catheterization, to make changes in the patient’s drug prescription. Ketoconazole 400 mg per day was started, the dose of vitamin D was increased to 14,000 IU per week, and ramipril 5 mg per day was prescribed due to secondary hypertension. In addition, given the severity of osteoporosis, it was decided to replace previously prescribed alendronate with zoledronic acid. Magnetic resonance imaging of the upper abdomen was performed on 06/19/2021, which demonstrated lobulated nodular thickening in the left adrenal gland with areas of decreased signal intensity in the T1 out-phase sequence, denoting the presence of fat, and homogeneous enhancement using contrast, measuring approximately 1.7 × 1.5 × 1.3 cm, suggestive of an adenoma. There was also a small nodular thickening in the lateral arm of the right adrenal, measuring approximately 0.8 × 0.6 cm, which was difficult to characterize due to its small dimensions and nonspecific appearance. PPNAD or carcinoma became an important etiological hypothesis for the case described when comparing the epidemiology in a young man and the clinical-laboratory-imaging findings of the differential diagnoses. According to a dialog with the patient and family, the group of experts opted for unilateral glandular surgical resection on the left side (11/11/2021), where more significant changes were visualized, as there was a possibility of malignancy in a young patient and to avoid a definitive adrenal insufficiency condition because of bilateral adrenalectomy. This would first allow the analysis of the material and follow-up of the evolution of the condition with the permanence of the contralateral gland. In the macroscopic analysis of the adrenalectomy specimen, adrenal tissue weighing 20 g and measuring 9.3 × 5.5 × 2.0 cm was described, completely surrounded by adipose tissue. The gland has a multinodular surface and varies between 0.2 and 1.6 cm in thickness, showing a cortex of 0.1 cm in thickness and a medulla of 1.5 cm in thickness (Fig. 4). Fig. 4 Left adrenal Full size image The microscopic analysis described the expansion of the zona fasciculate, with the formation of multiple nonencapsulated nodules composed of polygonal cells with ample and eosinophilic cytoplasm and frequent depletion of intracytoplasmic lipid content. No areas of necrosis or mitotic activity were observed. The histopathological picture is suggestive of cortical pigmented micronodular hyperplasia of the adrenal gland. For the final etiological definition and an indication of contralateral adrenalectomy, which could be unnecessary and would avoid chronic corticosteroid therapy, or else, it would be necessary to protect the patient from future complications with the maintenance of the disease in the right adrenal gland, it would be essential to search for mutations in the PRKAR1A, PDE11A, PDE8B and PRKACA genes [15]; however, such genetic analysis is not yet widely available, and the impossibility of carrying it out at the local level did not allow a complete conclusion of the case. Discussion Through the clinical picture presented and the research of several secondary causes for osteoporosis, it was possible to arrive at the diagnosis of Cushing syndrome [6]. There was symptomatic independent ACTH hypercortisolism, manifested by typical phenotypic changes, severe secondary osteoporosis, and arterial hypertension in a young patient. The diagnosis of Cushing’s syndrome is always challenging, given the presence of confounding factors such as the following: Physiological states of hypercortisolism—pseudo Cushing (strenuous exercise, pregnancy, uncontrolled diabetes, sleep apnea, chronic pain, alcohol withdrawal, psychiatric disorders, stress, obesity, glucocorticoid resistance syndromes); Cyclic or mild—subclinical Cushing’s pictures; Frequent and, even unknown, short- and long-term use of corticosteroids under different presentations; Increase in the general population incidence of diabetes and obesity; Screening tests with singularities for collection and individualized for different patient profiles. It is important to note that the basal morning cortisol measurement is not the ideal test to assess hypercortisolism and is better applied to the assessment of adrenal insufficiency. However, the hypercortisolism of the case was unequivocal, and this test was also shown to be altered several times. As no test is 100% accurate, the current guidelines suggest the use of at least two first-line functional tests that focus on different aspects of the pathophysiology of the hypothalamic‒pituitary‒adrenal axis to confirm the hypercortisolism state: 24-hours cortisol, nocturnal salivary cortisol, morning serum cortisol after suppression with 1 mg of dexamethasone or after Liddle 1. Given that night-time salivary cortisol would require hospitalization, the other suggested tests were chosen, which are easier to perform in this context [7, 8]. Subsequently, tests were performed to determine the cause of hypercortisolism, such as serum ACTH levels and adrenal CT. The suppressed ACTH denoted the independence of its action. CT showed bilateral adrenal nodules with more severe features: solid lesion, attenuation > 10 UI on noncontrast images, and contrast washout speed < 60% in 10 minutes. In this case, it is essential to make a broad clinical decision and dialog with the patient to weigh and understand the risks and benefits of surgical treatment [9]. Among the main diagnostic hypotheses for the differential diagnosis of bilateral adrenal hyperplasia are primary bilateral macronodular adrenal hyperplasia, McCune–Albright syndrome (MAS) and bilateral primary pigmented nodular hyperplasia (PPNAD) isolated or associated with Carney’s complex. Another possibility would be bilateral adrenocorticotropic hormone (ACTH)-dependent macronodular hyperplasia secondary to long-term adrenal stimulation in patients with Cushing’s disease (ACTH-secreting pituitary tumor) or ectopic ACTH production, but the present case did not present with ACTH elevation. Primary macronodular adrenal hyperplasia (nodules > 1 cm) predominates in women aged 50–60 years and may also be detected in early childhood (before 5 years) in the context of McCune–Albright syndrome. Most cases are considered sporadic; however, there are now several reports of familial cases whose presentation suggests autosomal dominant transmission. Several pathogenic molecular causes were identified in the table, indicating that it is a heterogeneous disease [10]. The pathophysiology occurs through the expression of anomalous ectopic hormone receptors or amplified eutopic receptors in the adrenals. It usually manifests in an insidious and subclinical way, with cortisol secretion mediated through receptors for gastric inhibitory peptide (GIP), vasopressin (ADH), catecholamines, interleukin 1 (IL-1), leptin, luteinizing hormone (LH), serotonin or others. Nodular development is not always synchronous or multiple; thus, hypercortisolism only manifests when there is a considerable increase in the number of adrenocortical cells, with severe steroidogenesis observed by cortisoluria greater than 3 times the upper limit of normal. Patients with mild Cushing’s syndrome should undergo screening protocols to identify aberrant receptors, as this may alter the therapeutic strategy. If there is evidence of abnormal receptors, treatment with beta-blockers is suggested for patients with beta-adrenergic receptors or with gonadotropin-releasing hormone (GnRH) agonists (and sex steroid replacement) for patients with LH/hCG receptors. In patients in whom aberrant hormone receptors are not present or for whom no specific pharmacological blockade is available or effective, the definitive treatment is bilateral adrenalectomy, which is known to make the patient dependent on chronic corticosteroid therapy [11]. Studies have shown the effectiveness of unilateral surgery in the medium and long term, opting for the resection of the adrenal gland of greater volume and nodularity by CT, regardless of the values obtained by catheterization of adrenal veins, but with the possibility of persistence or recurrence in the contralateral gland. Another possibility would be total unilateral adrenalectomy associated with subtotal contralateral adrenalectomy [12]. In McCune–Albright syndrome (MAS), there are activating mutations in the G-protein GNAS1 gene, generating autonomic hyperfunction of several tissues, endocrine or not, and there may be, for example, a constant stimulus similar to ACTH on the adrenal gland. In this case, pituitary levels of ACTH are suppressed, and adrenal adenomas with Cushing’s syndrome appear. Hypercortisolism may occur as an isolated manifestation of the syndrome or be associated with the triad composed of polyostotic fibrous dysplasia, café au lait spots with irregular borders and gonadal hyperfunction with peripheral precocious puberty. The natural history of Cushing’s syndrome in McCune-Albright syndrome (MAS) is heterogeneous, with some children evolving with spontaneous resolution of hypercortisolism, while others have a more severe condition, eventually requiring bilateral adrenalectomy [13]. PPNAD predominates in females, in people younger than 30 years, multiple and small (< 6 mm) bilateral pigmented nodules (surrounded by atrophied cortex), which can reach 1.5 cm in adulthood, with family genetic inheritance (66%) or sporadic inheritance (33%), and as part of the Carney complex reported in 40% of cases. In 70% of cases, inactivating mutations are identified in the PKA regulatory 1-alpha subunit (PRKAR1A), a tumor suppressor gene [14]. Osteoporosis is often associated with this condition [15]. One test that can distinguish patients with PPNAD from other primary adrenocortical lesions is cortisoluria after sequential suppression with low- and high-dose dexamethasone. In contrast to most patients with primary adrenocortical disease, who demonstrate no change in urinary cortisol, 70% of PPNAD patients have a paradoxical increase in urinary cortisol excretion [16]. The treatment of choice for PPNAD is bilateral adrenalectomy due to the high recurrence rate for primary adrenal disease [17]. Carney complex is a multiple neoplastic syndrome with autosomal dominant transmission, characterized by freckle-like cutaneous hyperpigmentation (lentiginosis), endocrine tumors [(PPNAD), testicular and/or thyroid tumors and acromegaly] and nonendocrine tumors, including cutaneous, cardiac, mammary, and osteochondral myxomas, among others. In the above case, the transthoracic echocardiogram of the patient on 03/18/2021 showed cavities of normal dimensions, preserved systolic and diastolic functions, no valve changes and no lentiginous skin areas and blue nevi, making the diagnosis of the syndrome less likely. The definitive diagnosis of Carney requires two or more main manifestations. Several related clinical components may suggest the diagnosis but not define it. The diagnosis can also be made if a key criterion is present and a first-degree relative has Carney or an inactivating mutation of the gene encoding PRKAR1A [18]. The adenoma is usually small in size (< 3 cm), similar to the nodules in this case; however, it is usually unilateral, with an insidious and mild evolution, especially in adult women over 35 years of age, producing only 1 steroid class. Carcinomas are usually large (> 6 cm), and only 10% are bilateral. They should be suspected mainly when the tumor presents with hypercortisolism associated with hyperandrogenism. They have a bimodal age distribution, with peaks in childhood and adolescence, as well as at the end of life [3]. Conclusion Early identification of Cushing’s syndrome, with measures based on the assessment of risks and benefits, remains the best way to prevent progression and reduce morbidity [2]. After 6 months of drug inhibition of steroidogenesis, blood pressure control and anti-osteoporotic therapy, the objective was to minimize the levels and deleterious metabolic effects of hypercortisolism, which could also harm the surgical procedure in the short and long term through infections, dehiscence, nonimmediate bed mobilization and cardiovascular events. Unilateral adrenalectomy was chosen, given the possibility of malignancy in a young patient and to avoid definitive surgical adrenal insufficiency if the adrenalectomy was bilateral. Despite the unavailability of genetic analysis for a precise etiological definition, it is possible to take efficient measures to avoid unnecessary consequences or damage. Availability of data and materials All data generated or analysed during this study are included in this published article [and its Additional file 1]. The datasets generated and/or analysed during the current study are available in the link https://ufjfedubr-my.sharepoint.com/:v:/g/personal/barbara_reis_ufjf_edu_br/EVpIR005sPZGlQvMJhIwSaUB0Hig4KOjhkG4D4cMggUwHA?e=Dk8tng. Abbreviations ACTH: Adrenocorticotropic hormone PPNAD: Bilateral primary pigmented nodular hyperplasia DXA: Dual energy X-ray absorptiometry GIP: Gastric inhibitory peptide GnRH: Gonadotropin-releasing hormone IL-1: Interleukin 1 BMD: Low bone mineral density LH: Luteinizing hormone MAS: McCune–Albright syndrome PRKAR1A: PKA regulatory 1-alpha subunit ADH: Vasopressin References Pedro AO, Plapler PG, Szejnfeld VL. 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Author information Authors and Affiliations Serviço de Endocrinologia, Hospital Universitário da Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil Bárbara Oliveira Reis, Christianne Toledo Sousa Leal, Danielle Guedes Andrade Ezequiel, Ana Carmen dos Santos Ribeiro Simões Juliano, Flávia Lopes de Macedo Veloso, Leila Marcia da Silva, Lize Vargas Ferreira, Mariana Ferreira & Gabriel Zeferino De Oliveira Souza Contributions All the authors contributed to the conception and design of the work and have approved the submitted version. All authors read and approved the final manuscript. Corresponding author Correspondence to Bárbara Oliveira Reis. Ethics declarations Ethics approval and consent to participate Not applicable. Consent for publication Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. 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Abstract Summary Cushing’s syndrome due to ectopic adrenocorticotropic hormone (ACTH) secretion (EAS) by a pheochromocytoma is a challenging condition. A woman with hypertension and an anamnestic report of a ‘non-secreting’ left adrenal mass developed uncontrolled blood pressure (BP), hyperglycaemia and severe hypokalaemia. ACTH-dependent severe hypercortisolism was ascertained in the absence of Cushingoid features, and a psycho-organic syndrome developed. Brain imaging revealed a splenial lesion of the corpus callosum and a pituitary microadenoma. The adrenal mass displayed high uptake on both 18F-FDG PET/CT and 68Ga-DOTATOC PET/CT; urinary metanephrine levels were greatly increased. The combination of antihypertensive drugs, high-dose potassium infusion, insulin and steroidogenesis inhibitor normalized BP, metabolic parameters and cortisol levels; laparoscopic left adrenalectomy under intravenous hydrocortisone infusion was performed. On combined histology and immunohistochemistry, an ACTH-secreting pheochromocytoma was diagnosed. The patient's clinical condition improved and remission of both hypercortisolism and catecholamine hypersecretion ensued. Brain magnetic resonance imaging showed a reduction of the splenial lesion. Off-therapy BP and metabolic parameters remained normal. The patient was discharged on cortisone replacement therapy for post-surgical hypocortisolism. EAS due to pheochromocytoma displays multifaceted clinical features and requires prompt diagnosis and multidisciplinary management in order to overcome the related severe clinical derangements. Learning points A small but significant number of cases of adrenocorticotropic hormone (ACTH)-dependent Cushing’s syndrome are caused by ectopic ACTH secretion by neuroendocrine tumours, which is usually associated with severe hypercortisolism causing severe clinical and metabolic derangements. Ectopic ACTH secretion by a pheochromocytoma is exceedingly rare but can be life-threatening, owing to the simultaneous excess of both cortisol and catecholamines. The combination of biochemical and hormonal testing and imaging procedures is mandatory for the diagnosis of ectopic ACTH secretion, and in the presence of an adrenal mass, the possibility of an ACTH-secreting pheochromocytoma should be taken into account. Immediate-acting steroidogenesis inhibitors are required for the treatment of hypercortisolism, and catecholamine excess should also be appropriately managed before surgical removal of the tumour. A multidisciplinary approach is required for the treatment of this challenging entity. Keywords: Adult; Female; White; Italy; Adrenal; Pituitary; Unique/unexpected symptoms or presentations of a disease; May; 2023 Background Cushing’s syndrome (CS) is a rare endocrine disease characterized by high levels of glucocorticoids; it increases morbidity and mortality due to cardiovascular and infectious diseases (1, 2, 3). To diagnose CS, adrenocorticotropic hormone (ACTH)-dependent disease must be distinguished from ACTH-independent disease, and pituitary ACTH production from ectopic production. About 20% of ACTH-dependent cases arise from ectopic ACTH secretion (EAS) (2, 3, 4). EAS is most often due to aberrant ACTH production by small-cell lung carcinoma or neuroendocrine tumours originating in the lungs or gastrointestinal tract; this, in turn, strongly increases cortisol production by the adrenal glands (3, 4, 5). Since the first-line treatment of EAS is the surgical removal of the ectopic ACTH-secreting tumour, its prompt and accurate localization is crucial. Rapid cortisol reduction by means of immediate-acting steroidogenesis inhibitors (4) is mandatory in order to treat the related endocrine, metabolic and electrolytic derangements. EAS by a pheochromocytoma is exceedingly rare and can be life-threatening. We describe the case of a woman with hypertension and a known ‘non-secreting’ left adrenal mass, who manifested uncontrolled blood pressure (BP), hyperglycaemia, hypokalaemia and psycho-organic syndrome associated with damage of the splenium of the corpus callosum. These findings were eventually seen to be related to an ACTH-secreting left pheochromocytoma, which was ascertained by hormonal evaluation and morphological and functional imaging assessment and confirmed by histopathology/immunostaining. Hormonal hypersecretion resolved after adrenalectomy and metabolic derangements normalized. Case presentation A 72-year-old woman with hypertension was taken to the emergency department because of increased BP (200/100 mm Hg). High BP (190/100 mmHg) was confirmed, whereas oxygen saturation (98%), heart rate (84 bpm) and lung and abdomen examination were normal. Electrocardiogram and chest x-ray were unremarkable. Captopril 50 mg orally, followed by intramuscular clonidine, normalized BP. The patient looked thin and reported significant weight loss (10 kg) over the previous 6 months; she was on antihypertensive therapy with bisoprolol 5 mg/day and irbesartan 150 mg/day, and ezetimibe 10 mg/day for dyslipidaemia. The patient’s records included a previous diagnosis in another hospital of normofunctioning multinodular goitre and a 2.5 cm-left solid inhomogeneous adrenal mass with well-defined margins, which was found on CT performed 6 years earlier during the work-up for hypertension. On the basis of hormonal data and absent uptake on 123I metaiodobenzylguanidine scintigraphy, the adrenal lesion had been deemed to be non-functioning and follow-up had been advised. Unfortunately, only initial cortisol (15.7 μg/dL) and 24-h urine-free cortisol (UFC) levels (32.5 μg/24 h) were retrievable; both proved normal. Investigations Blood chemistry showed neutrophilic leucocytosis, hyperglycaemia with increased glycated haemoglobin, severe hypokalaemia and metabolic alkalosis (Table 1). Potassium infusion (50 mEq in 500 mL saline/24 h) was rapidly started, together with a subcutaneous rapid-acting insulin analogue and prophylactic enoxaparin. The patient experienced mental confusion, hallucinations and restlessness; non-enhanced computed tomography (CT) of the brain revealed a hypodense area of the splenium of the corpus callosum, possibly due to metabolic damage (Fig. 1A). View Full Size Figure 1 Non-enhanced CT showing a hypodense area of the splenium of the corpus callosum (arrows), without mass effect (A, axial view). Contrast-enhanced MR image showing a hypointense pituitary lesion (arrow) which enhances more slowly than normal pituitary parenchyma, deemed suspicious for microadenoma (B, coronal view). FLAIR MR image showing hyperintense signal of the splenium of the corpus callosum (asterisk), which partially extended to the crux of the left fornix (arrow) (C, axial view). As the lesion showed no restricted diffusion on DWI (D, axial view), an ischaemic lesion was excluded. A progressive reduction in the extension of the hyperintense signal in the splenium of the corpus callosum (arrowheads) and in the crux of the left fornix (arrows) was observed on FLAIR MR images (2 months (E); 3 months (F); axial view). CT, computed tomography; DWI, diffusion-weighted imaging; FLAIR, fluid-attenuated inversion recovery; MR, magnetic resonance. Citation: Endocrinology, Diabetes & Metabolism Case Reports 2023, 2; 10.1530/EDM-22-0308 Download Figure Download figure as PowerPoint slide Table 1 Hormonal and biochemical evaluation of patient throughout hospitalization and follow-up. Normal range On hospital admission After surgery 10 days 2 months 3 months 6 months 9 months 12 months 16 months ACTH (pg/mL) 9–52 551 7 37 50 29.5 26 40.9 52 Morning cortisol† (µg/dL) 7–19.2 63.4 14 5.1 3.5 3.8 4.2 7.2 12.8 After 1 mg overnight dexamethasone  ACTH 583  Cortisol 60 DHEAS (µg/dL) 9.4–246 201 24-h urinalysis (µg/24 h)  Adrenaline 0–14.9 95.5  Noradrenaline 0–66 1133  Metanephrine 74–297 1927  Normetanephrine 105–354 1133 Chromogranin A 0–108 290 Renin (supine) (µU/mL) 2.4–29 3.9 14.6 Aldosterone (supine) (ng/dL) 3–15 3.4 12.5 LH (mIU/mL)* > 10 0.3 65.8 FSH (mIU/mL)* > 25 1.9 116 PRL (ng/mL) 3–24 13.7 FT4 (ng/dL) 0.9–1.7 1.1 1.2 FT3 (pg/mL) 1.8–4.6 1.1 2.7 TSH (µU/mL) 0.27–4.2 0.23 1.3 PTH (pg/mL) 15–65 166 Calcium (mg/dL) 8.2–10.2 8.2 Calcitonin (pg/mL) 0–10 1 Glycaemia (mg/dL) 60–110 212 69 73 83 Potassium (mEq/L) 3.5–5 2.4 3.3 3.9 4.2 3.7 5 4.4 3.9 Leucocytes (K/µL) 4.0–9.3 15.13 HbA1c (mmol/mol) 20–42 55 30 HCO3− (mEq/L) 22–26 41.8 *For menopausal age; †07:00–10:00 h. The patient was transferred to the internal medicine ward. Although potassium infusion was increased to 120 mEq/day, serum levels did not normalize; a mineralocorticoid receptor antagonist (potassium canreonate) was therefore introduced, but the effect was partial. In order to control BP, the irbersartan dose was increased (300 mg/day) and amlodipine (10 mg/day) was added. The combination of severe hypertension, newly occurring diabetes and resistant hypokalaemia prompted us to hypothesize a common endocrine aetiology. A thorough hormonal array showed very high ACTH and cortisol levels, whereas supine renin and aldosterone levels were in the low-normal range (Table 1). Since our patient proved repeatedly non-compliant with 24-h urine collection, UFC could not be measured. After an overnight 1 mg dexamethasone suppression test, cortisol levels remained unchanged, whereas ACTH levels slightly increased (Table 1). Notably, the patient showed no Cushingoid features. Gonadotropin levels were inappropriately low for the patient’s age; FT4 levels were normal, whereas FT3 and thyroid-stimulating hormone (TSH) levels were reduced and calcitonin levels were normal (Table 1). HbA1c levels were increased (Table 1). Finally, secondary hyperparathyroidism, associated with low-normal calcium levels and reduced vitamin D levels, was found (Table 1). Brain contrast-enhanced magnetic resonance (MR) imaging revealed a 5-mm median posterior pituitary microadenoma (Fig. 1B) and a hyperintense lesion of the splenium of the corpus callosum (Fig. 1C). Diffusion-weighted MR images of the lesion showed no restricted diffusion (Fig. 1D), thus excluding an ischaemic origin. Petrosal venous sampling for ACTH determination at baseline and after CRH stimulation was excluded, as it was deemed a high-risk procedure, given the patient's poor condition. Since the ACTH and cortisol levels were greatly increased and were associated with severe hypokalaemia, EAS was hypothesized; total-body contrast-enhanced CT revealed the left adrenal mass (3 cm), which showed regular margins and heterogeneous enhancement (Fig. 2A and B) and measured 25 Hounsfield units. There was no evidence of adrenal hyperplasia in the contralateral adrenal gland. The adrenal mass showed intense tracer uptake on both 18F-FDG PET/CT (Fig. 2C and D), suggestive of adrenal malignancy or functioning tumour, and 68Ga-DOTATOC PET/CT (Fig. 3), which is characteristic of a neuroendocrine lesion. No other sites of suspicious tracer uptake were detected. View Full Size Figure 2 Contrast-enhanced abdominal computed tomography showing a 3-cm left adrenal mass (arrow) with well-defined margins and inhomogeneus enhancement, deemed compatible with an adenoma (A, coronal view; B, axial view). The adrenal mass showed high uptake (SUV max: 7.3) on 18F-FDG PET/CT (C, coronal view; D, axial view). Citation: Endocrinology, Diabetes & Metabolism Case Reports 2023, 2; 10.1530/EDM-22-0308 Download Figure Download figure as PowerPoint slide View Full Size Figure 3 The left adrenal mass displaying very high uptake (SUV max: 40) on 68Ga-DOTATOC PET/CT (arrow, axial view). Citation: Endocrinology, Diabetes & Metabolism Case Reports 2023, 2; 10.1530/EDM-22-0308 Download Figure Download figure as PowerPoint slide Bisoprolol was withdrawn, and 24-h urinary catecholamine, metanephrine and normetanephrine levels proved significantly increased, as were chromogranin A levels (Table 1). In sum, an ACTH-secreting pheochromocytoma was suspected and the pituitary microadenoma was deemed a likely incidental finding. The patient’s mental state worsened, fluctuating from sopor to restlessness, which required parenteral neuroleptics and restraint. An electroencephalogram revealed a specific slowdown of cerebral electrical activity. Following rachicentesis, the cerebrospinal fluid showed pleocytosis (lympho-monocytosis), whereas a culture test and polymerase chain reaction for common neurotropic agents were negative. The neurologist hypothesized a psycho-organic syndrome secondary to severe metabolic derangement. Intravenous ampicillin, acyclovir and B vitamins were empirically started. The patient was transferred to the subintensive unit, where a nasogastric tube and central venous catheter were inserted, and enteral nutrition was started. Treatment Ketoconazole was started at a dosage of 200 mg twice daily; both cortisol and ACTH levels significantly decreased over a few days (Fig. 4), with a progressive decrease in glucose levels and normalization of potassium levels and BP on therapy. Subsequently, ketoconazole was titrated to 600 mg/day owing to a new increase in cortisol levels, which eventually normalized (Fig. 4). Of note, ACTH levels partially decreased on ketoconazole treatment (Fig. 4). View Full Size Figure 4 ACTH and cortisol levels throughout the patient’s hospitalization and follow-up. Citation: Endocrinology, Diabetes & Metabolism Case Reports 2023, 2; 10.1530/EDM-22-0308 Download Figure Download figure as PowerPoint slide Doxazosin 2 mg/day was added and the patient's systolic BP blood settled at around 100 mm Hg; after a few days, bisoprolol was restarted. Contrast-enhanced MR showed a partial reduction of the hyperintense splenial lesion (Fig. 1E). Despite the severe clinical condition and the high risks of adrenal surgery, the patient’s relatives strongly requested the procedure and laparoscopic left adrenalectomy was planned. Alpha-blocker and fluid infusion were continued, ketoconazole was withdrawn the day before surgery, and a 100 mg IV bolus of hydrocortisone was administered just before the operation, followed by 200 mg/day, at first in continuous infusion, then as a 100 mg bolus every 8 h. After the removal of the left adrenal mass, noradrenaline infusion was required, owing to the occurrence of severe hypotension. Outcome and follow-up Pathology revealed a 2.5 cm reddish-brown encapsulated tumour, which was compatible with pheochromocytoma (Fig. 5A and B); ACTH immunostaining was positive in about 30% of tumour cells (Fig. 5C). This confirmed the diagnostic hypothesis of an ACTH-secreting pheochromocytoma. The tumour was stained for Chromogranin A (Fig. 5D). There were no signs of adrenal cortex hyperplasia in the resected gland. Thorough germinal genetic testing, comprising the commonest pheochromocytoma/paraganglioma genes: CDKN1B, KIF1B, MEN1, RET, SDHA, SDHB, SDHC, SDHD, SDHAF2 and TMEM127, was negative. View Full Size Figure 5 Histological images of adrenal pheochromocytoma: the tumour is composed of well-defined nests of cells (‘zellballen’) (A; haematoxylin-eosin stain (HE), ×20) with pleomorphic nuclei with prominent nucleoli, basophilic or granular amphophilic cytoplasm (B; HE, ×40). The mitotic index was low: 1 mitosis per 30 high-power fields, and Ki-67 was 1%. On immunohistochemistry, cytoplasmatic ACTH staining was found in about 30% of tumour cells (C; ×20), whereas most tumour cells were stained for chromogranin A (D; ×20). Citation: Endocrinology, Diabetes & Metabolism Case Reports 2023, 2; 10.1530/EDM-22-0308 Download Figure Download figure as PowerPoint slide One week after surgery ACTH levels had dropped to a low-normal value: 7 pg/mL, and cortisol levels (before morning hydrocortisone bolus administration) were normal: 14 µg/dL (Fig. 4). The patient’s clinical status slowly improved and the nasogastric tube was removed; intravenous hydrocortisone was carefully tapered until withdrawal and high-dose oral cortisone acetate (62.5 mg/day) was started. This dose was initially required since BP remained low (systolic: 90 mm Hg); thereafter, cortisone was reduced to 37.5 mg/day. Plasma cortisol levels before morning cortisone administration were reduced (Fig. 4). A new MR of the brain showed a further partial reduction of the splenial lesion (Fig. 1F). The patient was discharged with normal off-therapy BP and metabolic parameters. During follow-up, she fully recovered, and BP and metabolic parameters remained normal. Gonadotropin levels became adequate for the patient’s age, and TSH and renin/aldosterone levels normalized (Table 1). Hypoadrenalism, however, persisted for more than 1 year; as the last hormonal evaluation, 16 months after surgery, showed normal baseline cortisol levels, the cortisone dose was tapered (12.5 mg/day) and further hormonal examination was scheduled (Table 1). ACTH and cortisol levels throughout the patient’s hospitalization and follow-up are shown in Fig. 4. Discussion The diagnosis of EAS is challenging and requires two steps: confirmation of increased ACTH and cortisol levels and anatomic distinction from pituitary sources of ACTH overproduction. Besides metabolic derangements (hyperglycaemia, hypertension), EAS-related severe hypercortisolism may cause profound hypokalaemia (3, 4, 5). In our patient, the combination of worsening hypertension, newly occurring diabetes and resistant hypokalaemia raised the suspicion of a common endocrine cause. ACTH-dependent severe hypercortisolism was ascertained, and subsequent brain MR revealed a pituitary microadenoma. The diagnosis of CS requires the combination of two abnormal test results: 24-h UFC, midnight salivary cortisol and/or abnormal 1 mg dexamethasone suppression testing (2, 6). ACTH evaluation (low/normal-high) is fundamental to tailoring the imaging technique. The very high cortisol levels found in our patient were unchanged after overnight dexamethasone testing, whereas UFC could not be assessed owing to the lack of compliance with urine collection. The accuracy of the UFC assays, however, may be impaired by cortisol precursors and metabolites. Salivary cortisol assessment was not performed since the specific assay is not available in our hospital. The combination of ACTH-dependent severe hypercortisolism and hypokalaemia prompted us to suspect EAS. The differential diagnosis between pituitary and ectopic ACTH-dependent CS involves high-dose (8 mg) dexamethasone suppression testing, which has relatively low diagnostic accuracy (6). Owing to the patient's very high cortisol levels and severe hypokalaemia, this testing was not performed, on account of the risks of administering corticosteroids in a patient already exposed to excessive levels (6). Furthermore, owing to the increase in ACTH levels observed after overnight dexamethasone testing, we postulated the possible occurrence of glucocorticoid-driven positive feedback on ACTH secretion, which has been described in EAS, including cases of pheochromocytoma (7). Finally, in the case of EAS suspected of being caused by pheochromocytoma, we do not recommend performing high-dose dexamethasone suppression testing, owing to the risk of triggering a catecholaminergic crisis (8). The dynamic tests commonly used to distinguish patients with EAS from those with Cushing's disease are the CRH stimulation test and the desmopressin stimulation test, either alone or in combination with CRH testing (6). Owing to the rapid worsening of our patient’s condition, dynamic testing was not done; however, the clinical picture and hormonal/biochemical data were suggestive of EAS. EAS is mainly (45–50%) due to neuroendocrine tumours, mostly of the lung (small-cell lung cancer and bronchial tumours), thymus or gastrointestinal tract; however, up to 20% of ACTH-secreting tumours remain occult (3, 4, 5). ACTH-secreting pheochromocytomas are responsible for about 5% of cases of EAS (3, 4, 9, 10). Indeed, this rate ranges widely, from 2.5% (11) to 15% (12), according to the different case series. Patients with EAS due to pheochromocytoma present with severe CS, overt diabetes mellitus, hypertension and hypokalaemia (3); symptoms of catecholamine excess may be unapparent (3), making the diagnosis more challenging. A recent review of 99 patients with ACTH- and/or CRH-secreting pheochromocytomas found that the vast majority displayed a Cushingoid phenotype (10); by contrast, another review of 24 patients reported that typical Cushingoid features were observed in only 30% of patients, whereas weight loss was a prevalent clinical finding (13). We hypothesized that the significant weight loss reported by our patient was largely due to the hypermetabolic state induced by catecholamines, which directly reduce visceral and subcutaneous fat, as recently reported (14). Our patient showed no classic stigmata of CS, owing to the rapid onset of severe hypercortisolism (10, 13), whereas she had worsening hypertension and newly occurring diabetes mellitus, which were related to both cortisol and catecholamine hypersecretion; hypokalaemia was deemed to be secondary to severe hypercortisolism. Indeed, greatly increased cortisol levels act on the mineralocorticoid receptors of the distal tubule after saturating 11β-hydroxysteroid dehydrogenase type 2, leading to hypokalaemia (4). Consequently, hypokalaemia is much more common (74–95% of patients) in EAS than in classic Cushing’s disease (10%) (3, 4, 10). This apparent mineralocorticoid excess suppresses renin and aldosterone secretion, as was ascertained in our patient. In this setting, the most effective way to manage hypokalaemia is to treat the hypercortisolism itself by administering immediate-acting steroidogenesis inhibitors, combined with potassium infusion and a mineralocorticoid receptor-antagonist (e.g. spironolactone) at an appropriate dosage (100–300 mg/day) (4). In ACTH-secreting pheochromocytoma, cortisol hypersecretion potentiates catecholamine-induced hypertension by stimulating the phenol-etholamine-N-methyl–transferase enzyme, which transforms noradrenaline to adrenaline (4). Indeed, in our patient, the significant ketoconazole-induced reduction in cortisol secretion led to satisfactory BP control on antihypertensive drugs. After the biochemical diagnosis of pheochromocytoma, a selective alpha-blocker was added, and after a few days, a beta-blocker was restarted in order to control reflex tachycardia (15). Our patient had greatly increased ACTH levels (>500 pg/mL) associated with very high cortisol levels (>60 µg/dL), which, together with the finding of hypokalaemia, prompted us to hypothesize EAS. With regard to these findings, ACTH levels are usually higher (>200 pg/mL) in patients with EAS than in those with CS due to a pituitary adenoma; however, considerable overlapping occurs (3, 11, 16). Most patients with ACTH-secreting pheochromocytomas in those series had ACTH levels >300 pg/mL, and a few had normal ACTH levels (9), thus complicating the diagnosis. In addition, patients with EAS usually have higher cortisol levels than those with ACTH-secreting adenomas (3, 11). In our patient, the left adrenal mass was deemed the culprit of EAS, and owing to very high urinary metanephrine levels, a pheochromocytoma was suspected. It can be assumed that the adrenal tumour, which was anamnestically reported as ‘non-secreting’, but on which only part of the initial hormonal data were available, was actually a pheochromocytoma at the time of the first diagnosis but displayed a silent clinical and hormonal behaviour. The mass subsequently showed significant uptake on both 18F-FDG PET/CT and 68Ga-DOTATOC PET/CT (4, 5). It is claimed that 68Ga-DOTATOC PET/CT provides a high grade (90%) of sensitivity and specificity in the diagnosis of tumours that cause EAS (4, 5); nevertheless, a recent systematic review reported much lower sensitivity (64%), which increased to 76% in histologically confirmed cases (17). In patients with EAS, immediate-acting steroidogenesis inhibitors are required in order to achieve prompt control of severe hypercortisolism (4). Ketoconazole is one of the drugs of choice since it inhibits adrenal steroidogenesis at several steps. In our patient, ketoconazole rapidly reduced cortisol levels to normal values, without causing hepatic toxicity (4). Moreover, ketoconazole proved effective at a moderate dosage (600 mg/day), which falls within the mean literature range (18, 19). However, dosages up to 1200–1600 mg/day are sometimes required in severe cases (usually EAS) (18, 19). Speculatively, our results might reflect an enhanced inhibitory action of ketoconazole at the adrenal level, which was able to override the strong ectopic ACTH stimulation. In addition, the finding that, following cortisol reduction, ACTH levels paradoxically decreased suggests an additive and direct effect of the drug. This effect has been observed in a few patients with EAS (20) and is supported by in vitro studies showing a direct anti-proliferative and pro-apoptotic effect of ketoconazole on ectopic ACTH secretion by tumours (21). Finally, the reduction in ACTH levels during treatment with steroidogenesis inhibitors prompts us to postulate the presence of glucocorticoid-driven positive feedback on ACTH secretion, as already described in neuroendocrine tumours (7, 20, 21). The coexistence of EAS and ACTH-producing pituitary adenoma is very rare but must be taken into account. In our case, we deemed the pituitary mass found on MR to be a non-secreting microadenoma. This hypothesis was strengthened by the finding that, following exeresis of the ACTH-secreting pheochromocytoma, ACTH normalized, hypercortisolism vanished and pituitary function recovered. These findings suggest that: (i) altered pituitary function at the baseline was secondary to the inhibitory effect of hypercortisolism; (ii) the excessive production of cortisol was driven by ACTH overproduction outside the pituitary gland, specifically within the adrenal gland tumour. In our patient, a few days after surgery, morning cortisol levels before hydrocortisone bolus administration were ‘normal’. Owing to both the half-life of hydrocortisone (8–12 h) and the supraphysiological dosage used, it is likely that a residual part of the drug, which cross-reacts in the cortisol assay, was still circulating at the time of blood collection, thus resulting in ‘normal’ cortisol values. Following the switch to oral cortisone, cortisol levels before therapy were low, thus confirming post-surgical hypocortisolism. Hypocortisolism remained throughout the first year after surgery, and glucocorticoid therapy was continued. Sixteen months after surgery, baseline cortisol levels returned to the normal range; cortisone therapy was therefore tapered and a further hormonal check was scheduled. Assessment of the cortisol response to ACTH stimulation testing would be helpful in order to check the resumption of the residual adrenal function. A peculiar aspect of our case was the occurrence of a psycho-organic syndrome together with the finding of a splenial lesion on brain imaging, which was deemed secondary to metabolic injury. Indeed, the increased cortisol levels present in patients with Cushing’s disease are detrimental to the white matter of the brain, including the corpus collosum, causing subsequent clinical derangements (22). Besides the direct effects of hypercortisolism, the splenial damage was also probably due to long-standing hypertension, worsened by newly occurring catecholamine hypersecretion and diabetes. Together with the normalization of cortisol and glycaemic levels, and of BP, a partial reduction in the splenial damage was observed on two subsequent MR examinations, and the patient's neurological condition slowly improved until she fully recovered. In our patient, thorough germinal genetic testing for the commonest pheochromocytoma/paraganglioma (PPGL) genes proved negative. Since approximately 40% of these tumours have germline mutations, genetic testing is recommended regardless of the patient’s age and family history. In the absence of syndromic, familial or metastatic presentation, the selection of genes for testing may be guided by the tumour location and biochemical phenotype. Alterations of the PPGL genes can be divided into two groups: 10 genes (RET, VHL, NF1, SDHD, SDHAF2, SDHC, SDHB, SDHA, TMEM127 and MAX) that have well-defined genotype–phenotype correlations, thus allowing to tailor imaging procedures and medical management, and a group of other emerging genes, which lack established genotype–phenotype associations; for patients in whom mutations of genes belonging to this second group are detected, and hence hereditary predisposition is established, only general medical surveillance and family screening can be planned (23, 24). In conclusion, our case highlights the importance of investigating patients with hypertension and metabolic derangements such as diabetes and hypokalaemia, since these findings may be a sign of newly occurring EAS, which, in rare cases, may be due to an ACTH-secreting pheochromocytoma. Since the additive effect of cortisol and catecholamine can cause dramatic clinical consequences, the possibility of an ACTH-secreting pheochromocytoma should be taken into account in the presence of an adrenal mass. EAS must be considered an endocrine emergency requiring urgent multi-specialist treatment. Surgery, whenever possible, is usually curative, and anatomic brain damage, as ascertained in our patient, may be at least partially reversible. Declaration of interest The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported. Funding This study did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector. The study was approved by the Local Ethics Committee (no: 732/2022). Patient consent The patient provided written informed consent. Author contribution statement All authors contributed equally to the conception, writing and editing of the manuscript. L Foppiani took care of the patient during hospitalization and in the outpatient department, performed the metabolic and endocrine work-up, conceived the study, analysed the data and wrote the manuscript. MG Poeta evaluated the patient during hospitalization with regard to neurological problems and planned the related work-up (brain imaging procedures and rachicentesis). M Rutigliani analysed the histological specimens and performed immunohistochemical studies. S Parodi performed CT and MR scans and analysed the related images. U Catrambone performed the left adrenalectomy. L Cavalleri performed general anaesthesia and assisted the patient during the surgical and post-surgical periods. G Antonucci revised the manuscript. P Del Monte helped in the endocrine work-up, in the evaluation of hormonal data and in the revision of the manuscript. A Piccardo performed 18F-FDG PET/CT and analysed the related images. Acknowledgement The work of Prof Silvia Morbelli in performing and analysing 68Ga-DOTATOC PET/CT is gratefully acknowledged. References 1↑ Pivonello R, Isidori AM, De Martino MC, Newell-Price J, Biller BMK, Colao A. Complications of Cushing's syndrome: state of the art. The Lancet Diabetes & Endocrinology 2016 4 611–629. (https://doi.org/10.1016/S2213-8587(1600086-3) Search Google Scholar Export Citation 2↑ Fleseriu M, Auchus R, Bancos I, Ben-Shlomo A, Bertherat J, Biermasz NR, Boguszewski CL, Bronstein MD, Buchfelder M, Carmichael JD, et al.Consensus on diagnosis and management of Cushing's disease: a guideline update. Lancet. 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Abstract N-of-1 trials can serve as useful tools in managing rare disease. We describe a patient presenting with a typical clinical picture of Cushing’s Syndrome (CS). Further testing was diagnostic of ectopic Adrenocorticotropic Hormone (ACTH) secretion, but its origin remained occult. The patient was offered treatment with daily pasireotide at very low doses (300 mg bid), which resulted in clinical and biochemical control for a period of 5 years, when a pulmonary typical carcinoid was diagnosed and dissected. During the pharmacological treatment period, pasireotide was tentatively discontinued twice, with immediate flare of symptoms and biochemical markers, followed by remission after drug reinitiation. This is the first report of clinical and biochemical remission of an ectopic CS (ECS) with pasireotide used as first line treatment, in a low-grade lung carcinoid, for a prolonged period of 5 years. In conclusion, the burden of high morbidity caused by hypercortisolism can be effectively mitigated with appropriate pharmacological treatment, in patients with occult tumors. Pasireotide may lead to complete and sustained remission of hypercortisolism, until surgical therapy is feasible. The expression of SSTR2 from typical carcinoids may be critical in allowing the use of very low drug doses for achieving disease control, while minimizing the risk of adverse events. Download PDF (2083K)

Objective: The first-line treatment for Cushing’s disease is transsphenoidal surgery, after which the rates of remission are 60 to 80%, with long-term recurrence of 20 to 30%, even in those with real initial remission. Drug therapies are indicated for patients without initial remission or with surgical contraindications or recurrence, and ketoconazole is one of the main available therapies. The objective of this study was to evaluate the safety profile of and the treatment response to ketoconazole in Cushing’s disease patients followed up at the endocrinology outpatient clinic of a Brazilian university hospital. Patients and methods: This was a retrospective cohort of Cushing’s disease patients with active hypercortisolism who used ketoconazole at any stage of follow-up. Patients who were followed up for less than 7 days, who did not adhere to treatment, or who were lost to follow-up were excluded. Results: Of the 172 Cushing’s disease patients who were followed up between 2004 and 2020, 38 received ketoconazole. However, complete data was only available for 33 of these patients. Of these, 26 (78%) underwent transsphenoidal surgery prior to using ketoconazole, five of whom (15%) had also undergone radiotherapy; seven used ketoconazole as a primary treatment. Ketoconazole use ranged from 14 days to 14.5 years. A total of 22 patients had a complete response (66%), three patients had a partial response (9%), and eight patients had no response to treatment (24%), including those who underwent radiotherapy while using ketoconazole. Patients whose hypercortisolism was controlled or partially controlled with ketoconazole had lower baseline 24-h urinary free cortisol levels than the uncontrolled group [times above the upper limit of normal: 0.62 (SD, 0.41) vs. 5.3 (SD, 8.21); p < 0.005, respectively] in addition to more frequent previous transsphenoidal surgery (p < 0.04). The prevalence of uncontrolled patients remained stable over time (approximately 30%) despite ketoconazole dose adjustments or association with other drugs, which had no significant effect. One patient received adjuvant cabergoline from the beginning of the follow-up, and it was prescribed to nine others due to clinical non-response to ketoconazole alone. Ten patients (30%) reported mild adverse effects, such as nausea, vomiting, dizziness, and loss of appetite. Only four patients had serious adverse effects that warranted discontinuation. There were 20 confirmed episodes of hypokalemia among 10/33 patients (30%). Conclusion: Ketoconazole effectively controlled hypercortisolism in 66% of Cushing’s disease patients, being a relatively safe drug for those without remission after transsphenoidal surgery or whose symptoms must be controlled until a new definitive therapy is carried out. Hypokalemia is a frequent metabolic effect not yet described in other series, which should be monitored during treatment. Introduction Cushing’s disease (CD) results from a pituitary tumor that secretes adrenocorticotropic hormone (ACTH), which leads to chronic hypercortisolism. It is a potentially fatal disease with high morbidity and a mortality rate of up to 3.7 times than that of the general population (1–4) associated to several clinical–metabolic disorders caused by excess cortisol and/or loss of circadian rhythm (5). In general, its management is a challenge even in reference centers (6, 7). Transsphenoidal surgery (TSS), the treatment of choice for CD, results in short-term remission in 60 to 80% of patients (8). However, recurrence rates of 20 to 30% are found in long-term follow-up, even in those with clear initial remission (9). Drug therapies can help control excess cortisol in patients without initial remission, in cases of recurrence, and in those with contraindications or high initial surgical risk (10). Nevertheless, specific drugs that act on the pituitary adenoma, which could directly treat excess ACTH, have a limited effect, and only pasireotide is approved for this purpose in Brazil (11, 12). In this scenario, adrenal steroidogenesis blockers are important. One such off-label medication is the antifungal drug ketoconazole, a synthetic imidazole derivative that inhibits the enzymes CYP11A1, CYP17, CYP11B2, and CYP11B1. Because of its hepatotoxicity and the availability of other drugs, it has been withdrawn from the market in several countries (13). In Europe, it is still approved for use in CD, although in the United States, it is recommended for off-label use almost in CD (14–16). Due to the potential benefits for hypercortisolism, ketoconazole has been replaced by levoketoconazole, which the European Union has recently approved for CD with a lower expected hepatotoxicity (17). Thus, when adrenal inhibitors are used as an alternative treatment for CD, information about the outcomes of drugs such as ketoconazole are important. Clinical studies on these effects in CD are scarce, mostly retrospective, multicenter, or from developed countries (14, 18). A recent meta-analysis on the therapeutic modalities for CD included only four studies (246 patients) that evaluated urinary cortisol response as a treatment outcome and eight studies (366 patients) describing the prevalence of some side effects: change in transaminase activity, digestive symptoms, skin rash, and adrenal insufficiency. Hypokalemia was not mentioned in this meta-analysis (19). The objective of this study was to evaluate the safety profile of and treatment response to ketoconazole in CD patients followed during a long term in the endocrinology outpatient clinic of a Brazilian university hospital. Patients and methods Patients We retrospectively evaluated 38 patients (27 women) diagnosed with CD. These patients, whose treatment included ketoconazole at any time between 2004 and 2020, are part of a prospective cohort series from the Hospital de Clínicas de Porto Alegre neuroendocrinology outpatient clinic. The diagnostic criteria for hypercortisolism were based on high 24-h urinary free cortisol levels (24-h UFC) in at least two samples, non-suppression of serum cortisol after low-dose dexamethasone testing (>1.8 µg/dl), and/or loss of cortisol rhythm (midnight serum cortisol >7.5 µg/dl or midnight salivary cortisol >0.208 nmol/L). CD was diagnosed by normal or elevated ACTH levels, evidence of pituitary adenoma >0.6 cm on magnetic resonance image (MRI), and ACTH central/periphery gradient on inferior petrosal sinus catheterization when MRI was normal or showed an adenoma <0.6 cm. CD was considered to be in remission after the improvement of hypercortisolism symptoms or clinical signs of adrenal insufficiency, associated with serum cortisol within reference values, normalization of 24-h UFC and/or serum cortisol <1.8 μg/dl at 8 am after 1 mg dexamethasone overnight, and/or normalization of midnight serum or salivary cortisol. In patients with active disease, to evaluate the ketoconazole treatment response, 24-h UFC was used as a laboratory parameter, as recommended in similar publications (14, 16, 20, 21), but in some cases, we considered elevated late night salivary cortisol and/or 1 mg dexamethasone overnight cortisol (even with normal 24-h UFC), given the greater assessment sensitivity seen through these two methods in the detection of early recurrence when compared with 24-h UFC (22). Inclusion criteria We included patients with CD and active hypercortisolism who used ketoconazole either as primary treatment, after TSS without hypercortisolism remission, or after a recurrence. Exclusion criteria We excluded patients with CD and active hypercortisolism who used ketoconazole but had <7 days of follow-up, irregular outpatient follow-up, treatment non-adherence, and incomplete medical records or those who were lost to follow-up. Evaluated parameters Prior to ketoconazole treatment, all patients underwent an assessment of pituitary function and hypercortisolism, including serum cortisol, ACTH, 24-hour UFC, cortisol suppression after 1 mg dexamethasone overnight, midnight serum cortisol, and/or midnight salivary cortisol. The evaluated parameters were sex, age at diagnosis, weight, height, prevalence and severity of hypertension and DM, pituitary tumor characteristics, prior treatment (surgery, radiotherapy, or other medications), symptoms at disease onset, biochemical tests (renal function, hepatic function, and lipid profile), number of medications used to treat associated comorbidities, data on medication tolerance, and reasons for discontinuation, when necessary. The clinical parameters observed during treatment were control of blood pressure and hyperglycemia, anthropometric measurements (weight, height, and body mass index), jaundice, and any other symptoms or adverse effects reported by patients. The biochemical evaluation included fasting glucose, glycated hemoglobin, lipid profile (total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides), markers of liver damage (transaminases, bilirubin, gamma-glutamyl transferase, and alkaline phosphatase), electrolytes (sodium and potassium), and renal function (creatinine and urea). Hypecortisolism was accessed preferentially by 24-h UFC, however, late-night salivary cortisol and cortisol after 1 mg overnight dexamethasone could also be used. Study design This retrospective cohort study included patients with CD who were followed up at the Hospital de Clínicas de Porto Alegre Endocrinology Division, with their medical records from the first outpatient visit and throughout clinical follow-up collected. This study was approved by the Hospital de Clínicas de Porto Alegre Research Ethics Committee (number 74555617.0.0000.5327). Outcomes Hypercortisolism was considered controlled when the 24-h UFC and/or late-night salivary cortisol (LNSC) and/or overnight 1 mg dexamethasone suppression test (DST) levels were normalized in at least two consecutive assessments. Hypercortisolism was considered partially controlled when there was a 50% over-reduction in 24-h UFC and/or LNSC and/or DST levels but still above normal. A reduction lower than 50% in these parameters was considered as non-response. We also assessed the ketoconazole doses that resulted in 24-h UFC normalization, maximum dose, medication tolerance, adverse effects, and changes in liver, kidney, and biochemical function. Due to the characteristics of this study, these outcomes were periodically evaluated in all patient consultations, which occurred usually every 2 to 4 months. Data collection This retrospective cohort evaluated outpatient medical records and any tests indicated by the attending physician as a pragmatic study. Ketoconazole use followed the department’s care protocol, which is based on national and international guidelines (4), and all patients received a similar care routine: the recommended initial prescription was generally taken in two to six doses at 100 to 300 mg/day. It was then increased by 200 mg every 2 to 4 months until hypercortisolism was controlled or side effects developed, especially those related to liver function. The maximum prescription was 1,200 mg/day. Clinical follow-up of these patients was performed 30 days after starting the medication and every 2–4 months thereafter (23). Clinical, anthropometric, laboratory, and other exam data were collected through a review of the hospital’s electronic medical records for the entire follow-up period. Data from the first and last consultation were considered in the final analysis of all parameters. Statistical analysis Baseline population characteristics were described as mean and standard deviation (SD) or median with interquartile ranges (25–75) for continuous variables. The chi-square test was used to compare qualitative variables, and Student’s t-test or ANOVA was used to compare the quantitative variables. The Mann–Whitney U-test was used for unpaired data. P-values <0.05 were considered significant. Statistical analysis was performed in SPSS 18.0 (SPSS Inc., Chicago, IL, USA) and R package geepack 1.3-1. Results Treatment with ketoconazole was indicated for 41 of the 172 CD patients. In 3/41 patients, ketoconazole was unallowed due to concomitant liver disease, and 38 received ketoconazole during CD treatment between 2004 and 2020. Of these, five were excluded due to insufficient data to determine the response to ketoconazole (short treatment time, irregular follow-up, incomplete medical records, or lost to follow-up). The baseline characteristics of every sample are shown in Table 1. Thus, 33/41 patients were included in the final analysis. The patients were predominantly women (84.2%) and white (89.5%); 11 had microadenoma, 15 had macroadenoma, and 11 had no adenoma visualized. In 12/33 patients, pituitary imaging was not performed immediately before starting ketoconazole. Hypertension was observed in 26 patients (78%) and DM in 12 patients (36%). The mean age at CD diagnosis was 31.7 years. Table 1 TABLE 1 Baseline clinical data of Cushing’s disease patients treated with ketoconazole. Of the 33 patients with complete data, 26 (78%) underwent TSS prior to starting ketoconazole, five of whom (15%) had also undergone radiotherapy. Thus, seven patients used ketoconazole as primary treatment since performing a surgical procedure was impossible at that time. Of these, four had no response to ketoconazole, one had a partial response, and two had a complete response. At follow-up, four of these patients underwent their first TSS, and three continued the ketoconazole therapy, achieving full UFC control. Among those who used ketoconazole after TSS (n = 26), 20 had a complete response, two had a partial response, and four had no response. Figure 1 shows the study flow chart and patient distribution throughout the treatment. Figure 1 FIGURE 1 Flowchart of ketoconazole treatment in Cushing's disease patients. Individual patient data are described in Table 2. The duration of ketoconazole use ranged from 14 days (in one patient who used it pre-TSS) to 14.5 years. The total follow-up time of the 22 patients with controlled CD ranged from 3 months to 14.5 years, with a mean of 5.33 years and a median of 4.8 years. Table 2 TABLE 2 Individual data. Therapeutic response Relative therapeutic response data are described in Table 3. Patients whose hypercortisolism was controlled or partially controlled with ketoconazole had lower baseline 24-h UFC than the uncontrolled group [times above the upper limit of normal: 0.62 (SD, 0.41) vs. 5.3 (SD, 8.21); p < 0.005, respectively], in addition to more frequent prior TSS (p < 0.04). In some patients (4/33), 24-h UFC was in the normal range at the beginning of ketoconazole therapy, but they were prescribed with the medication due to the clinical recurrence of CD associated to cortisol non-suppression after 1 mg dexamethasone overnight and/or abnormal midnight salivary or serum cortisol. Table 3 TABLE 3 Baseline characteristics of Cushing’s disease patients according to therapeutic response to ketoconazole. Figure 2 shows that the prevalence of uncontrolled patients remained stable over time (approximately 30%) despite dose adjustments or association with other drugs, which led to no differences. When analyzing only the results of the last follow-up visit (eliminating fluctuations during follow-up), 22 patients had a complete response (66%), three patients had a partial response (9%), and eight patients had no response to ketoconazole treatment (24%), which includes patients who underwent radiotherapy during ketoconazole treatment. Figure 2 FIGURE 2 Prevalence of controlled hypercortisolism during follow-up of Cushing's disease patients treatesd with ketoconazole. During follow-up, no significant differences were found in blood pressure control or in dehydroepiandrosterone sulfate, cortisol, ACTH, or glucose levels. Worsening of hypertension control was observed in association with hypokalemia in some cases, as described in side effects. The ketoconazole doses ranged from 100 to 1,200 mg per day, and there were no significant dose or response differences between the groups (Table 4). Figure 3 shows the patients, their dosages, and 24-h UFC control at the first and last consultation, showing a trend toward hypercortisolism reduction in approximately 70% of the cohort (25 of 33). Only four patients used doses lower than 300 mg at the end of follow-up. One of them used before TSS and suspended its use after surgery. One patient, who has already undergone radiotherapy, discontinued ketoconazole due to intolerance, despite adequate control of hypercortisolism. Another one, who had also undergone radiotherapy, was lost to follow-up when it was controlled using 100 mg daily, and one remained controlled using 200 mg, without previous radiotherapy. Table 4 TABLE 4 Final dose of ketoconazole used in patients with Cushing’s disease. Figure 3 FIGURE 3 First and last consultation 24çhour UFC results vs. ketoconazole dosage in Cushing's disease patients. Side effects Regarding adverse effects (Table 5), there was no significant difference between the controlled/partially controlled group and the uncontrolled group regarding liver enzyme changes or drug intolerance. Mild adverse effects, including nausea, vomiting, dizziness, and loss of appetite, occurred in 10 patients (30%). Only four patients had serious adverse effects that warranted discontinuing the medication. In two cases, ketoconazole was discontinued due to a significantly acute increase in liver enzymes (drug-induced hepatitis) during the use of 400 and 800 mg of ketoconazole. Non-significant elevation of transaminases (up to three times the normal value) was observed in three cases. A slight increase in gamma-glutamyltransferase occurred in six patients. In these nine patients with elevated liver markers, the daily dose ranged from 400 to 1,200 mg. None of those with mild increases in liver markers needed to discontinue ketoconazole. Table 5 TABLE 5 Adverse effects of ketoconazole in Cushing’s disease patients treated with ketoconazole. One female patient developed pseudotumor cerebri syndrome, which was treated with acetazolamide. She did not need to discontinue ketoconazole, having used it for more than 10 years without new side effects and achieving complete control of hypercortisolism (24). Another patient became pregnant during follow-up while using the medication, but no maternal or fetal complications occurred (25). Hypokalemia was also observed during follow-up. Twenty episodes of reduced potassium levels occurred in 10 patients over the course of treatment. Of these episodes, six occurred in controlled patients, three in partially controlled patients, and 11 in uncontrolled patients (Table 6). The hypokalemia was managed with spironolactone (25 to 100 mg) and oral potassium supplementation. Table 6 TABLE 6 Characteristics of Cushing’s disease patients who developed hypokalemia during ketoconazole treatment. Ketoconazole and associations Of the patients who used an association of cabergoline and ketoconazole, one did so since the beginning of follow-up, while another nine were prescribed cabergoline during follow-up due to non-response to ketoconazole alone. Of these 10 patients, two did not start the medication due to problems in obtaining the drug. Thus, in two of the nine patients on the maximum tolerated dose of ketoconazole or who could not tolerate a higher dose due to hepatic enzymatic changes, 1.5–4.5 mg of cabergoline per week was associated. In patients not controlled with ketoconazole plus cabergoline, mitotane (two patients) or pasireotide (two patients) was added. Only two of nine patients responded to the combination of cabergoline and ketoconazole. Data on these associations are shown in Table 7. Table 7 TABLE 7 Effects of associating cabergoline with ketoconazole in Cushing’s disease patients. Considering that one of the indications for the treatment of hypercortisolism may be complementary to radiotherapy, we analyzed the eight patients who underwent radiotherapy after transsphenoidal surgery. In these patients, doses of ketoconazole from 200 to 1,200 mg were used, and in six patients there was a normalization of the UFC in 1 to 60 months of treatment. Thus, the association of ketoconazole with radiotherapy was effective in normalizing the 24-h UFC in 75% of cases. Clinical follow-up New therapeutic approaches were attempted in some patients during follow-up: radiotherapy (eight patients), new TSS (five patients), and bilateral adrenalectomy (four patients). At the end of this analysis, 11 patients remained on ketoconazole, all with controlled hypercortisolism. Among the 11 patients who were not fully controlled by the last visit, five were using ketoconazole as pre-TSS therapy and underwent TSS as soon as possible, while three others underwent radiotherapy and two underwent bilateral adrenalectomy. One patient was lost to follow-up. Discussion According to the current consensus about CD, drug treatment should be reserved for patients without remission after TSS, those who cannot undergo surgical treatment, or those awaiting the effects of radiotherapy (4, 16). Drugs available in this context may act as adrenal steroidogenesis blockers (ketoconazole, osilodrostat, metyrapone, mitotane, levoketoconazole, and etomidate), in pituitary adenoma (somatostatinergic receptor ligands—pasireotide), dopamine receptor agonists (cabergoline), or glucocorticoid receptor blockers (mifepristone) (16, 26). Among these alternatives, the drug of choice still cannot be determined. Thus, the best option must be established individually, considering aspects such as remission potential, safety profile, availability, cost, etc. (16, 27, 28). For over 30 years, ketoconazole has been prescribed off-label for CD patients with varied rates of remission of hypercortisolism, and it can be used in monotherapy or associated with other drugs (29, 30). The Brazilian public health system does not provide drugs for the treatment of CD, and among medications with a better profile for controlling hypercortisolism, such as osilodrostat, levoketoconazole, and pasireotide, only pasireotide has been approved by the national regulatory authority (ANVISA). Due to such pragmatic considerations, ketoconazole is among the most commonly used drugs in our health system, whether recently associated or not with cabergoline (7). In this cohort, the most prevalent response type was complete (66%). Since 75% of the CD patients who used ketoconazole had a complete or partial response, there was a clear trend towards improvement in hypercortisolism. When only those who used ketoconazole post-TSS were evaluated, the rate of control increased to 76%. We found that patients with a higher initial 24-h UFC tended to have less control of excess cortisol, a difference that was not observed when analyzing ketoconazole dose or follow-up time. In our series and at the prescribed doses, the combination of cabergoline and ketoconazole was not effective in the management of hypercortisolism since only two of nine patients (22%) had their 24-hour UFC normalized. However, it should be observed that this association was used in patients who had more severe CD and, consequently, were less likely to have a favorable response. The effects of cabergoline in CD patients remain controversial, although some studies have shown promising responses (31, 32). Previous reviews found that the efficacy of ketoconazole for hypercortisolism control was quite heterogeneous, ranging from 14 to 100% in 99 patients (33, 34). Our cohort’s response rate was lower than that of Sonino et al. (89%) (20) but higher than that of a multicenter cohort by Castinetti et al. (approximately 50%) (14). Regarding other smaller series (35–37) our results reinforce some findings that demonstrate a percentage of control greater than 50% of the cases. Our analyses showed a trend toward a response that continued, with some oscillations, over time. The rate of uncontrolled patients remained stable over time (approximately 30%), regardless of association with other drugs (cabergoline, mitotane, or pasireotide) or dose adjustments. Speculatively, it would appear that patients who respond to ketoconazole treatment would show some type of response as soon as therapy begins. Our cohort has the longest follow-up time of any study on ketoconazole use in CD, nearly 15 years. Our results demonstrate that patients who benefit from ketoconazole (i.e., control of hypercortisolism and associated comorbidities) can safely use it for a long term since those who did not experience liver enzyme changes at the beginning of treatment also had no long-term changes. Another relevant information for clinical practice is the result of treatment with ketoconazole associated with radiotherapy, which demonstrated normalizing the 24-h UFC in 75% of cases, a finding that reinforces the use of this therapeutic combination, especially in cases that are more resistant to different treatment modalities. As described in the literature, adverse effects, such as nausea, vomiting, dizziness, headache, loss of appetite, and elevated transaminases, are relatively frequent (38). In our cohort, 10 patients (30%) had mild adverse effects, and four (12%) had more serious adverse effects requiring discontinuation. In other studies, up to 20% of patients required discontinuation due to side effects (14). We documented 20 episodes of hypokalemia during ketoconazole treatment, some with worsening blood pressure control. In most cases, hypokalemia has occurred in association with the use of diuretic drugs, which may have potentiated potassium spoliation, reinforcing the need of stringent surveillance in hypertensive Cushing’s disease patients using this combination. It can also result from the enzymatic blockade that could lead to the elevation of adrenal mineralocorticoid precursors (pex. deoxycorticosterone), with consequent sodium retention and worsening hypertension. Although it has not been analyzed in other series with ketoconazole, this side effect has been observed in patients who received other adrenal-blocking drugs, such as osilodrostat and metyrapone (16). This alteration seems to be transient in some patients; in our series, it was managed by suspending drugs that could worsen hypokalemia and introducing spironolactone and/or potassium supplementation. Hypokalemia may also result from continuing intense adrenal stimulation by ACTH and changes in the activity of the 11-beta-hydroxysteroid dehydrogenase enzyme, which increase the mineralocorticoid activity of cortisol, as observed in patients with severe hypercortisolism in uncontrolled CD (39). Hypogonadism occurred in one male patient. In two adolescent patients (one female and one male), hypercortisolism was effectively controlled without altering the progression of puberty. As described in other cohorts, this effect was expected due to the high doses, which block adrenal and testicular androgen production (20). Thus, our findings confirm previous reports in the literature and add important information about the side effects and safety of long-term ketoconazole use in CD treatment. Our data reinforce the current recommendations about ketoconazole for recurrent cases or those refractory to surgery, including proper follow-up by an experienced team specializing in evaluating clinical and biochemical responses and potential adverse effects (7, 18, 40). Despite the severity of many of our CD patients, no ketoconazole-related death occurred during follow-up, including long-term observation. On the other hand, no patient progressed to definitive remission of hypercortisolism, even after many years of treatment with ketoconazole. Conclusions In our cohort of patients, ketoconazole proved to be an effective and safe alternative for CD treatment, although it can produce side effects that require proper identification and management, allowing effective long-term treatment. We found side effects that have been rarely described in the literature, including hypokalemia and worsening hypertension, which require specific care and management. Thus, ketoconazole is an effective alternative for CD patients who cannot undergo surgery, who do not achieve remission after pituitary surgery, or who have recurrent hypercortisolism. Data availability statement The raw data supporting the conclusions of this article will be made available by the authors without undue reservation. Ethics statement The studies involving human participants were reviewed and approved by the Hospital de Clínicas de Porto Alegre Research Ethics Committee. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements. Author contributions CV and MAC created the research format. CV, RBM, and MCBC realized the search on medical records. CV performed the statistical analysis. MAC, ACVM, and TCR participated in the final data review and discussion. ACVM participated in the final data review and discussion as volunteer collaborator. All authors contributed to the article and approved the submitted version. Funding This work was supported by the “Coordenação de Aperfeiçoamento de Pessoal de Nı́vel Superior” (CAPES), Ministry of Health - Brazil, through a PhD scholarship; and the Research Incentive Fund (FIPE) of Hospital de Clı́nicas de Porto Alegre. Acknowledgments The authors would like to thank the HCPA Research and Graduate Studies Group (GPPG) for the statistical technical support provided by Rogério Borges. We also thank the Research Incentive Fund of Hospital de Clínicas de Porto Alegre and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), by funds applied. We also thank the Graduate Program in Endocrinology and Metabolism (PPGEndo UFRGS) for all the support in the preparation of this research. Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. 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Best Pract Res Clin Endocrinol Metab (2021) 35(1):101490. doi: 10.1016/j.beem.2021.101490 PubMed Abstract | CrossRef Full Text | Google Scholar Keywords: Cushing’s disease, Cushing’s syndrome, hypercortisolism, treatment, ketoconazole Citation: Viecceli C, Mattos ACV, Costa MCB, Melo RBd, Rodrigues TdC and Czepielewski MA (2022) Evaluation of ketoconazole as a treatment for Cushing’s disease in a retrospective cohort. Front. Endocrinol. 13:1017331. doi: 10.3389/fendo.2022.1017331 Received: 11 August 2022; Accepted: 06 September 2022; Published: 07 October 2022. Edited by: Luiz Augusto Casulari, University of Brasilia, Brazil Reviewed by: Juliana Drummond, Federal University of Minas Gerais, Brazil Monalisa Azevedo, University of Brasilia, Brazil Copyright © 2022 Viecceli, Mattos, Costa, Melo, Rodrigues and Czepielewski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. *Correspondence: Mauro Antonio Czepielewski, maurocze@terra.com.br Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. From https://www.frontiersin.org/articles/10.3389/fendo.2022.1017331/full