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E. Ferrante, M. Barbot, A. L. Serban, F. Ceccato, G. Carosi, L. Lizzul, E. Sala, A. Daniele, R. Indirli, M. Cuman, M. Locatelli, R. Manara, M. Arosio, M. Boscaro, G. Mantovani & C. Scaroni Journal of Endocrinological Investigation (2021)Cite this article 286 Accesses 6 Altmetric Metricsdetails Abstract Purpose Dynamic testing represents the mainstay in the differential diagnosis of ACTH-dependent Cushing’s syndrome. However, in case of undetectable or detectable lesion < 6 mm on MRI, bilateral inferior petrosal sinus sampling (BIPSS) is suggested by current guidelines. Aim of this study was to analyze the performance of CRH, desmopressin and high-dose dexamethasone suppression test (HDDST) in the differential diagnosis of ACTH-dependent Cushing’s syndrome as well as the impact of invasive and noninvasive tests on surgical outcome in patients affected by Cushing’s disease (CD). Methods Retrospective analysis on 148 patients with CD and 26 patients with ectopic ACTH syndrome. Results Among CD patients, negative MRI/lesion < 6 mm was detected in 97 patients (Group A); 29 had a 6–10 mm lesion (Group and 22 a macroadenoma (Group C). A positive response to CRH test, HDSST and desmopressin test was recorded in 89.4%, 91·4% and 70.1% of cases, respectively. Concordant positive response to both CRH/HDDST and CRH/desmopressin tests showed a positive predictive value of 100% for the diagnosis of CD. Among Group A patients with concordant CRH test and HDDST, no difference in surgical outcome was found between patients who performed BIPSS and those who did not (66.6% vs 70.4%, p = 0.78). Conclusions CRH, desmopressin test and HDDST have high accuracy in the differential diagnosis of ACTH-dependent CS. In patients with microadenoma < 6 mm or non-visible lesion, a concordant positive response to noninvasive tests seems sufficient to diagnose CD, irrespective of MRI finding. In these patients, BIPSS should be reserved to discordant tests. Introduction Cushing’s syndrome (CS) is a rare and potentially fatal condition due to chronic exposure to cortisol. After excluding exogenous glucococorticoid assumption from any route, the diagnosis is based on clinical suspicion and further confirmed with appropriate testing as suggested by Endocrine Society Guidelines [urinary free cortisol (UFC), late night serum/salivary cortisol and 1 mg dexamethasone suppression test] [1]. Once the diagnosis of endogenous hypercortisolism is confirmed, the measurement of morning ACTH levels allows to discriminate ACTH-dependent from ACTH-independent CS that originates from primary adrenal disorders. Among ACTH-dependent CS, the most common form is caused by an ACTH-secreting pituitary tumor, a condition named Cushing’s disease (CD), accounting for about 80% of all cases, whereas the rest is due to an ectopic source (EAS); even though ACTH levels are usually higher in EAS than in CD, there is a significant overlap between these two conditions, thus further diagnostic procedures are needed [1]. Desmopressin (DDAVP) stimulatory test is helpful in suggesting risk of recurrence in the post-neurosurgical follow-up, but it seems to have a limited diagnostic utility in the differential diagnosis of ACTH-dependent CS due to the expression of vasopressin receptors in both CD and EAS [2]. Conversely, high-dose dexamethasone suppression test (HDDST) and corticotropin-releasing hormone (CRH) test have been widely used for this purpose and represent the mainstay in the differential diagnosis of ACTH-dependent CS forms [3,4,5,6]. Despite their satisfactory accuracy, there is no consensus on how to interpret their results [7]. Previous studies found that the presence of concordant clear-cut response to both HDDST and CRH test is able to exclude the diagnosis of EAS, irrespective of magnetic resonance imaging (MRI) finding [8, 9]. Even though MRI with intravenous gadolinium administration is certainly useful for individuation of the pituitary tumor, it results in little help in about 30% of cases due to tiny dimensions, localization and characteristics of the ACTH-secreting pituitary adenomas [10]. Conversely, radiological studies may sometimes disclose abnormalities with no functional significance, the so-called “pituitary incidentalomas”, that have been found in about 10% of healthy individuals [11], as in up to 38% of patients with EAS [12]. However, it is noteworthy that the finding of a pituitary incidentalomas larger than 6 mm in patients with EAS is usually very rare [13]. The presence of a microadenoma is therefore not enough for hypercortisolism to be labeled as pituitary-dependent and the role of hormonal tests is crucial for a correct diagnosis. When discordant results to dynamic tests and/or when pituitary MRI shows a lesion < 6 mm, bilateral inferior petrosal sinus sampling (BIPSS) is still recommended as the gold-standard procedure to achieve correct differential diagnosis due to its high sensitivity and specificity [7]. However, even BIPSS is not always fully reliable; false negative results are indeed possible in case of anatomical variations of the venous drainage from the cavernous sinuses to the jugular veins or when BIPSS is performed in a low-normal cortisolemic phase, as might happen in cyclic CS or during treatment with cortisol-lowering medications [14]. Furthermore, BIPSS requires hospitalization, is time- and cost-consuming and in few instances might lead to severe complications [15, 16]. Given the fact that BIPSS is not 100% accurate, has poor reliability to suggest intrapituitary localization/lateralization and has some drawbacks [17], we collected clinical, biochemical and neuroradiological data of a large series of CD patients as well as biochemical and neuroradiological data of a group of EAS patients with the following aims: (i) to describe the responsiveness to dynamic testing (CRH test, DDAVP test and HDDST) and its performance in the differential diagnosis of ACTH-dependent Cushing’s syndrome in possible different scenarios given by MRI finding; (ii) to assess whether the decision of BIPSS execution can affect surgical outcome of patients affected by Cushing’s disease. Patients and methods We performed a retrospective analysis on 148 patients (F/M 113/35, mean age 42.4 ± 14.2 years) affected by CD followed at 2 tertiary care centers in Italy between 2000 and 2017 [Endocrinology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico of Milan (62 patients); Endocrinology Unit, Department of Medicine-DIMED, University of Padova (86 patients)]. The diagnosis of hypercortisolism was performed on the basis of typical clinical features in the presence of at least two of the following abnormal tests: high 24-h UFC levels, loss of circadian rhythm in plasma/salivary cortisol and lack of cortisol suppression after 1 mg of dexamethasone overnight [1]. The diagnosis of ACTH-dependent hypercortisolism was confirmed in case of detectable baseline ACTH plasma levels (> 20 ng/L) [18]. Pituitary MRI (magnet strength ranging from 1.5 to 3.0 TESLA over the study period) with gadolinium was performed in all patients and reviewed by experienced neuroradiologists. Differential diagnosis of ACTH-dependent hypercortisolism was established through: (i) CRH test (positive response: ACTH and/or cortisol plasma levels increase by more than 50% and/or 20%, respectively) [12, 18,19,20]; (ii) high-dose dexamethasone suppression test (HDDST) (positive response: serum cortisol levels reduction to a value of < 50% of the basal level) [19]; (iii) DDAVP test (positive response: increase of both ACTH and cortisol greater than 30% and 20%, respectively) [21, 22]. For CRH and DDAVP tests, all patients were evaluated after an overnight fast; blood samples for ACTH and cortisol measurements were collected − 15, 0, 15, 30, 45, 60, 90 and 120 min after intravenous bolus injection of human CRH 100 µg or DDAVP 10 µg, respectively. For HDDST, dexamethasone 8 mg was administered orally at 23.00 h and serum cortisol levels were measured between 8.00 and 9.00 a.m. on the next morning. The decision whether to perform bilateral inferior petrosal sinus sampling (BIPSS) was guided by clinical judgement considering neuroradiological and biochemical findings. After catheter placement, ACTH was measured simultaneously in a blood sample obtained from each petrosal sinus and from a peripheral vein before and 1, 3, 5, and 10 min after the injection of 1 µg/Kg of CRH. An inferior petrosal sinus to periphery ratio (IPS:P) ≥ 2 at baseline or ≥ 3 after CRH administration was considered as positive response [23]. All patients included in this study underwent transsphenoidal surgery (TSS) performed by neurosurgeons with recognized expertise in the management of pituitary diseases. The pituitary origin of ACTH secretion was then confirmed by immediate (serum cortisol < 138 nmol/L within 7 days following TSS) and/or sustained biochemical remission [hypoadrenalism (morning serum cortisol < 138 nmol/L or lack of cortisol response to Synacthen stimulation test considering a cut-off of 500 nmol/L) for at least 6 months] after TSS and/or histological examination (defined as positive immunostaining for ACTH on the adenomatous tissue). Finally, data describing biochemical responses to CRH test, DDAVP test and HDDST and pituitary MRI in a group of 26 patients (14 of which were presented in a previous publication) [9] with histologically confirmed ectopic ACTH syndrome (EAS) were also collected. Statistical analysis Data are shown using mean ± standard deviation for normally distributed continuous variables or median and interquartile range (IQR) for non-Gaussian data and proportion for categorical parameters. Categorical data were analyzed using the χ2 test or the Fisher exact test if the expected value was < 5. Continuous parameters with normal distribution were compared using the t test and non-Gaussian data using the non-parametric test of Mann Whitney. The relation between two or more variable was assessed through logistic regression in case of binary dependent variable and linear regression in case of continuous dependent variable. Sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) were calculated with 95% confidence intervals (CI) using the exact binomial method. All statistical analyses were performed using SPSS, version 25 (IBM, Cary, NC, USA). Results Neuroradiological findings Patients with CD were divided into three groups on the basis of MRI results; group A included 97 patients (65.5%) with negative imaging (n = 40, 27% of total) or with a pituitary lesion < 6 mm (n = 57 patients, 38.5%); group B those with visible pituitary adenoma sized between 6 and 10 mm (29 subjects, 19.6%), while group C accounted for patients with macroadenoma (22 patients, 14.9%) (Fig. 1). Fig. 1 Different groups of patients according to MRI findings Full size image Among patients with EAS, seven had a microadenoma < 6 mm, while pituitary imaging was negative in 19. Biochemical characteristics at baseline Demographic, basal and dynamic biochemical characteristics and remission rates of three groups of patients affected by CD are summarised in Table 1. Table 1 Demographic, basal and dynamic biochemical characteristics and remission rates of three groups of patients Full size table Basal levels of cortisol, ACTH and UFC were evaluated for each group. Because of different assay methods performed during time, we preferred to use relative UFC (UFC/upper normal limit ratio). Patients of Group C showed higher basal ACTH levels compared to patients with negative MRI imaging or microadenomas (Group A + B) [90(54.5–113.5) vs 44.6(33.7–65.6), p < 0.001), without difference between Group A and Group B. No difference in basal cortisol and relative UFC levels was found between groups. Late night salivary cortisol levels were evaluated in 73 patients (47 of Group A, 13 of Group B and C) without any difference between groups. Suppression test Overall, a positive response to HDDST was observed in 91.4% of cases of CD. The rate of responders to HDDST was similar between negative MRI/microadenomas (Group A + B) and macroadenomas (respectively 92.6% vs 83.3%, p = 0.18) and no differences were found in cortisol levels and percentage of cortisol reduction after HDDST among the three different groups of patients (Table 1). Six out of 26 patients affected by EAS were responsive to HDDST (23.1%). HDDST had a 91% SE, 77% SP, 95% PPV and 62% NPV to diagnose Cushing’s disease (Table 2). Table 2 Diagnostic performance of positive response to CRH test, HDDST and their combination for the correct identification of Cushing’s disease Full size table Dynamic tests Overall, CRH test was positive in 89.4% of CD subjects. The response rate was significantly higher in patients with negative MRI/microadenomas (Group A + B) with respect to those with macroadenomas (91.7% vs 75%, p = 0.04), without difference between Group A and Group B. Likewise, negative MRI/microadenomas showed a higher response in terms of ACTH [140.5 (71.9–284.9) vs 82 (26.4–190.9) p = 0.02] and cortisol percentage increase [61.8 (30.7–92.8) vs 36.8 (15.6–63.1), p = 0.03]. As far as DDAVP is concerned, a positive response was recorded in 70.1% of the whole cohort. In this case, unlike CRH test, the response rate was significantly higher in patients with macroadenomas than in those with negative MRI/microadenomas (90% vs 66.3%, p = 0.03). However, no differences between negative MRI/microadenomas and macroadenomas in terms of percentage increase of ACTH and cortisol were found. Concordance of positive responses between CRH test and HDDST was observed in 81.5% of all patients (82.4% in Group A, 88.4% in Group B and 66.6% of Group C) without any difference between groups. In four cases, a negative response to both tests was recorded; all these patients had a macroadenoma with a minimum diameter of 20 mm. Concordant positive responses to CRH and DDAVP tests were observed in 62.6% of patients (62.9% in Group A, 56.5% in Group B and 68.4% in Group C, p = NS between groups). In Group A, the concordance rate between CRH and DDAVP was significantly lower than that observed between CRH test and HDDST (62.9% vs 81.5%, p = 0.035). Additionally, six patients (four of Group A, one of Group B and one of Group C) showed a negative response to both tests. With regards to EAS, one patient had a positive response to CRH test and six patients to HDDST, respectively. Data regarding DDAVP test were available in 22 out of 26 patients: in this subgroup, a false positive response was observed in 11 patients. However, no patient showed a concordant positive response to CRH test and HDDST or to CRH test and DDAVP test. Conversely, two patients responded to both HDDST and DDAVP test. Although it is beyond the aim of this paper, our data confirm previous studies reporting a higher sensitivity of CRH in respect to HDDST and DDAVP test in this setting [24,25,26]. CRH test showed a SE of 89%, SP of 96%, PPV of 99% and NPV of 62% for the diagnosis of CD (Table 2). The combination of the concordant positive responses to CRH test and HDDST performed better than single tests, reaching a 100% SP and PPV irrespective of pituitary MRI. Considering only the patients with negative imaging or a pituitary lesion < 6 mm, the SE, SP, PPV and NPV of combined positive responses were 82%, 100%, 100% and 62%, respectively (Table 2). On the other hand, combined negative responses in this subgroup of patients showed a SP and PPV of 100% for the diagnosis of EAS. Similarly, a positive response to both CRH test and DDAVP test reached a SP and PPV of 100% for the diagnosis of CD (Table 3). Table 3 Diagnostic performance of positive response to DDAVP test or to the combination DDAVP/CRH and DDAVP/HDDST for the correct identification of Cushing’s disease Full size table Bilateral inferior petrosal sinus sampling in CD BIPSS was performed in 29/97 patients of Group A and 1/29 patient of Group B. In particular, 20 of 29 patients of Group A had a negative MRI. In four out of these patients, CRH and HDDST were discordant (two negative results for each test) and BIPSS confirmed a pituitary origin of CS. In the other 16 cases, a positive response to both tests was observed: in 15 cases BIPSS confirmed the diagnosis of CD, while a central/periphery ratio of 2.91 after CRH administration was recorded in one case. The latter patient underwent TSS and CD was then confirmed by immediate and long-term remission of disease. Notably, no patient of Group A presented a negative response to both CRH test and HDDST, while four patients presented a combined negative response to CRH and DDAVP tests. In the remaining nine patients of Group A, MRI showed a visible microadenoma < 6 mm and BIPSS confirmed the diagnosis of CD both in concordant (n = 6) and discordant (n = 3) patients. BIPSS was not consistent with a pituitary origin in a patient of Group B with discordant tests. However, as her pretest probability of having CD was high (she was a young female without any suggestive features of ectopic CS and no lesion at thoracoabdominal computed tomography), also in this case the patient underwent TSS and both short and long-term remission confirmed the diagnosis of CD. No complications were observed in 29/30 patients after BIPSS. One patient died about 24 h after the procedure because of cardiac rupture. Since autopsy revealed a left ventricular free-wall rupture after asymptomatic acute myocardial infarction and cortisol related myopathy, this event was considered as unlikely related to BIPSS. Remission rates after surgery and role of BIPSS in CD patients with inconclusive neuroradiological imaging Overall, surgical remission was achieved in 107/148 (72.3%) patients. No difference between groups was found, also considering all patients with negative MRI or microadenomas (Group A + B) with respect to those with macroadenomas (Group C) (73.8% vs 63.6%, p = 0.31). Finally, when considering patients of Group A with concordant positive responses to HDDST and CRH test (n = 75), no difference in surgical outcome was found between patients who performed BIPSS and those who did not [respectively, 14/21 (66.6%) vs 38/54 (70.4%), p = 0.78] (Fig. 2). Fig. 2 Remission rate in patients of Group A with concordant positive tests Full size image Discussion Differential diagnosis of ACTH-dependent CS is challenging and to date a single best approach in the diagnostic work-up of these patients does not exist. Whereas the usefulness of stimulatory and suppression tests is widely accepted, their role to the light of positive MRI (pituitary adenoma < or > 6 mm) or negative findings is still a matter of debate. In the latter case, although BIPSS still represents the gold-standard procedure for differential diagnosis regardless the results of dynamic tests [7, 18], different clinical approaches and opinions are reported in the literature. In a recent opinion statement by members of the Italian Society of Endocrinology, Italian Society of Neurosurgery and Italian Society of Neuroradiology that summarizes different strategies adopted in the prescription of BIPSS [27], the authors report two studies in which BIPSS did not show any influence on neurosurgical remission rates. In the first one, Bochicchio and coll. retrospectively analyzed data from 668 patients affected by CD and described that in 98 subjects who underwent BIPSS, surgical failure was similar to patients who did not [28]; however, in this cohort CRH and TRH tests but not HDDST, were performed and selection criteria for BIPSS were not clearly reported. In the second one, Jehle and coll. performed a retrospective analysis of 193 patients with ACTH-dependent CS [29]; also in this case, BIPSS did not affect remission rate after TSS as far as recurrence and long-term remission rates. The procedure was reserved to patients with equivocal scan and/or biochemical tests; however, biochemical evaluation consisted of ACTH and UFC levels, while CRH test was not performed and data about HDDST were lacking in all but six patients. In a subsequent review about the role of BIPSS in CS, Zampetti et al. [30] suggested that, on the basis of authors’ experience, BIPSS should not be performed in patients with positive response to CRH test (defined as increase > 50% in ACTH and > 30% in cortisol), particularly if a consistent suppression to HDDST is present, independently of MRI findings. This opinion was finally remarked by Losa et al. [14] which pointed out CRH test as the main factor in providing indication to BIPSS. In this area of controversy, we performed a retrospective analysis on 148 patients with CD and 26 patients with EAS aiming to evaluate the role non-invasive tests in the diagnostic work-up, with secondary focus on the need of BIPSS in CD patients with inconclusive neuroradiological examination. In all 148 patients of our cohort, the diagnosis of CD was confirmed by biochemical remission after TSS, histology and/or > 6 months post-surgical hypoadrenalism. In agreement with previous data, our results confirm that CRH test and HDDST have high accuracy in differential diagnosis of ACTH-dependent CS [8, 9, 27]. As a whole, a positive response was observed in 89.4% and 91.4% of patients with CD, and in 3.8% and 23.1% of patients with EAS, respectively. More importantly, the combination of concordant positive responses to CRH test and HDDST reaches 100% specificity and PPV, thus allowing the diagnosis of CD irrespective of MRI findings. Otherwise, a single-test approach is not able to reach a specificity of 100%. The same performance is maintained in the subgroup of patients with negative MRI or with a microadenoma < 6 mm. Furthermore, in this subgroup, a negative response to both CRH test and HDDST is sufficient to make the diagnosis of EAS. Interestingly, in CD patients, the response rate to CRH test, as far as ACTH and cortisol percentage increase, were significantly higher in patients with microadenomas or negative imaging in respect to those with macroadenomas. A similar observation was recently reported in a group of 149 CD patients where macroadenomas tended to show a lower increase of ACTH after CRH compared to microadenomas [9]. As a negative correlation between baseline secretion and ACTH and cortisol responses to CRH in CD patients has been described [31], suggesting in this context a different degree of negative feedback impairment at the pituitary level, the finding of higher baseline ACTH levels in our patients may represent the most likely explanation for this observation. Accordingly, the highest rate of false negative responses to dynamic tests were observed in patients with macroadenomas, in which a false negative result to both CRH and HDDST was recorded in four cases; nevertheless, in this condition BIPSS is already overlooked due to the low pretest probability of the co-existence of a pituitary macroadenoma and an ectopic CS. The role of DDAVP test in differential diagnosis of ACTH-dependent CS is still controversial and a high frequency of false positive results in patients with EAS has been reported [2]. However, in a recent work including 167 patients with CD and 27 patients with EAS, the positive response to both CRH and DDAVP test showed a positive predictive value of 100% for CD in patients with negative MRI and negative computed tomography scan [32]. In our study, similarly to CRH test and HDDST, also the combination of positive responses to both CRH and DDAVP tests reaches a specificity and PPV of 100% for the diagnosis of CD. However, DDAVP test presents low sensitivity and specificity, thus resulting in a high prevalence of false negative and false positive results as well as a concordance rate significantly lower than that observed for CRH test and HDDST in patients with negative MRI or with a microadenoma < 6 mm. In addition, in four of these patients we recorded a concordant negative response to CRH and DDAVP tests that might have resulted in misdiagnosis. Therefore, our data indicate that DDAVP test may represent a valid alternative, in particular when discordant results arise from other dynamic tests, but CRH test, HDDST and their combination perform better and reduce the need to perform BIPSS. On the other hand, it is well recognized that DDAVP may have an important role in the post-surgical follow-up of CD patients, as the persistence or reappearance of a positive response may precede the clinical recurrence of disease [21, 22, 33,34,35,36,37,38]. In our series, BIPSS confirmed the diagnosis of CD in 28 out of 30 patients who underwent this procedure. Two negative cases included one patient with a pituitary adenoma sized between 6 and 10 mm but discordant CRH test and HDDST and another one with negative imaging and concordant tests. Notably, in the latter case, a borderline central/periphery ratio of 2.91 was recorded. Nevertheless, diagnosis of CD was subsequently proven by remission after neurosurgery, suggesting that BIPSS returned a false negative result in both patients. The proportion of false negative we observed is in line with previous literature data reporting a prevalence of 3–19%, possibly related to anatomical or biochemical variations of disease [14, 17, 27, 30, 39, 40]. Furthermore, BIPSS is burdened by possible complications. In particular, minor adverse events (i.e., groin hematoma, tinnitus, otalgia) have been reported in about 4% of patients, while severe complications (i.e., brainstem infarction, subarachnoid haemorrhage, pulmonary and deep venous thrombosis) are expected in less than 1% of cases [27, 30]. As reported above, in our series one patient died 24 h after BIPSS due to cardiac rupture, while no complications in the other subjects were recorded. Although our fatal event was unlikely related to the procedure and complications are rare, all these observations point out the need for an accurate selection of patients referred to BIPSS. Following the results of diagnostic performance analysis, in those patients with concordant positive responses to CRH test and HDDST but inconclusive neuroradiological findings (i.e., negative imaging or pituitary adenoma < 6 mm), the execution of BIPSS did not improve surgical outcome. Then, our data do not support the routine use of BIPSS in this subgroup of CD patients, in whom BIPSS could have been avoided in 22 out of 29 subjects. In this setting, contrarily to what the current guidelines propose [7, 13, 18, 19], CRH test and HDDST seems to be sufficient to confirm the diagnosis of CD and to provide indication to pituitary surgery. Similarly, a negative response to both tests pointed toward EAS diagnosis; in this circumstance BIPSS can be avoided too. Indeed, the present study does not propose to remove BIPSS from the diagnostic work-up of ACTH-dependent CS diagnosis, but to restrict its use when really necessary. Our study has some limitations: first, its retrospective nature, leading in particular to an inhomogeneous selection of patients referred to BIPSS. Second, our data do not allow to draw conclusions about patients with intermediate pituitary lesion between 6 and 10 mm. Although our approach was to avoid BIPSS even in case of discordant results, except in the presence of clinical features suggestive for ectopic CS (rapid onset, hypokalemia, advanced age), these cases can still represent matter of debate. On the other side, the strength is represented by the comprehensive and punctual biochemical and diagnostic characterization of patients which in our view makes our results very reliable. 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Author information Author notes E. Ferrante and M. Barbot have equally contributed to this work. Affiliations Endocrinology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico di Milano, Via Francesco Sforza, 35, 20122, Milan, Italy E. Ferrante, A. L. Serban, G. Carosi, E. Sala, R. Indirli, M. Arosio & G. Mantovani Endocrinology Unit, Department of Medicine DIMED, University of Padova, Padua, Italy M. Barbot, F. Ceccato, L. Lizzul, A. Daniele, M. Cuman, M. Boscaro & C. Scaroni Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy A. L. Serban Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy G. Carosi, R. Indirli, M. Arosio & G. Mantovani Neurosurgery Department, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico di Milano, Milan, Italy M. Locatelli Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy M. Locatelli Department of Neurosciences, University of Padua, Padua, Italy R. Manara Corresponding author Correspondence to G. Mantovani. Ethics declarations Conflict of interests All authors declare no competing interests. Ethical approval The study was approved by the Ethics Committee of Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico of Milan (Comitato Etico Milano Area 2, number 651_2019). Informed consent All subjects gave their written informed consent for the use of their clinical data for research purposes. 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/. Reprints and Permissions Cite this article Ferrante, E., Barbot, M., Serban, A.L. et al. Indication to dynamic and invasive testing in Cushing’s disease according to different neuroradiological findings. J Endocrinol Invest (2021). https://doi.org/10.1007/s40618-021-01695-1 Download citation Received13 October 2020 Accepted18 October 2021 Published26 October 2021 DOIhttps://doi.org/10.1007/s40618-021-01695-1 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 Cushing’s disease ACTH-dependent Cushing’s syndrome Differential diagnosis Bilateral inferior petrosal sinus sampling From https://link.springer.com/article/10.1007/s40618-021-01695-1

Personal Stories: From my bio: (At the NIH in October 1987) The MRI still showed nothing, so they did a Petrosal Sinus Sampling Test. That scared me more than the prospect of surgery. (This test carries the risk of stroke and uncontrollable bleeding from the incision points.) Catheters were fed from my groin area to my pituitary gland and dye was injected. I could watch the whole procedure on monitors. I could not move during this test or for several hours afterwards to prevent uncontrollable bleeding from a major artery. The test did show where the tumor probably was located. Also done were more sophisticated dexamethasone suppression tests where drugs were administered by IV and blood was drawn every hour (they put a heplock in my arm so they don't have to keep sticking me). I got to go home for a weekend and then went back for the surgery... _____ From Karen's Story: https://cushingsbios.com/2016/11/18/doc-karen-pituitary-and-bla-bio/ At that time, there was evidence of a pit tumor but it wasn’t showing up on an MRI. So, I had my IPSS scheduled. An IPSS stands for Inferior Petrosal Sinus Sampling. It is done because 60 % of Cushing’s based pituitary tumors are so small that they do not show up on an MRI. Non Cushing’s experts do not know this so they often blow patients off, even after the labs show a high level of ACTH in the brain through blood work. An overproduction of the hormone ACTH from the pituitary communicates to the adrenal glands to overproduce cortisol. Well, the IPSS procedure is where they put catheters up through your groin through your body up into your head to draw samples to basically see which side of your pituitary the extra hormone is coming from, thus indicating where the tumor is. U of C is the only place in IL that does it. ... I was scheduled to get an IPSS at U of C on June 28th, 2011 to locate the tumor. Two days after the IPSS, I began having spontaneous blackouts and ended up in the hospital for 6 days. The docs out here had no clue what was happening and I was having between 4-7 blackouts a day! My life was in danger and they were not helping me! We don’t know why, but the IPSS triggered something! But, no one wanted to be accountable so they told me the passing out, which I was not doing before, was all in my head being triggered by psychological issues. They did run many tests. But, they were all the wrong tests. I say all the time; it’s like going into Subway and ordering a turkey sandwich and giving them money and getting a tuna sandwich. You would be mad! What if they told you, “We gave you a sandwich!” Even if they were to give you a dozen sandwiches; if it wasn’t turkey, it wouldn’t be the right one. This is how I feel about these tests that they ran and said were all “normal”. The doctors kept telling us that they ran all of these tests so they could cover themselves. Yet, they were not looking at the right things, even though, I (the patient) kept telling them that this was an endocrine issue and had something to do with my tumor! Well, guess how good God is?!!!! ... Fast forward, I ended up in the hospital with these blackouts after my IPSS. The doctors, including MY local endocrinologist told me there was no medical evidence for my blackouts. In fact, he told the entire treatment team that he even doubted if I even had a tumor! However, this is the same man who referred me for the IPSS in the first place! I was literally dying and no one was helping me! We reached out to Dr. Ludlam in Seattle and told him of the situation. He told me he knew exactly what was going on. For some reason, there was a change in my brain tumor activity that happened after my IPSS. No one, to this day, has been able to answer the question as to whether the IPSS caused the change in tumor activity. The tumor, for some reason, began shutting itself on and off. When it would shut off, my cortisol would drop and would put me in a state of adrenal insufficiency, causing these blackouts! Dr. Ludlam said as soon as we were discharged, we needed to fly out to Seattle so that he could help me! The hospital discharged me in worse condition then when I came in. I had a blackout an hour after discharge! But get this…The DAY the hospital sent me home saying that I did not have a pit tumor, my IPSS results were waiting for me! EVIDENCE OF TUMOR ON THE LEFT SIDE OF MY PITUITARY GLAND!!! _____ From Kirsty: https://cushingsbios.com/2013/06/25/kirsty-kirstymnz-ectopic-adrenal-bio/ The hardest of all these was what they call a petrusal vein sampling (this is where they insert a catheter into the groin through the femoral vein which goes up to the base of the brain to look at the pituitary, they do this while awake – I could actually feel them moving around in my head.) This test concluded that my Cushing’s was being caused by a tumor somewhere other than the pituitary (this only happens in 1% of cases, and there is about a 1 in 10 million chance of getting it). The question now was “where is the tumor?” _____ Find other bios with which mention this test at https://cushingsbios.com/tag/ipss/ __________ This topic on these message boards: https://cushings.invisionzone.com/forum/54-css-ct-ipss-ivp-mri-np-59-scan-octreoscan-pss-sonogram-ultrasound/ __________ Thoughts from Dr. James Findling: https://cushieblogger.com/2019/03/24/cushings-syndrome-expert-a-standout-in-clinical-practice/ Another defining moment in my career from a research perspective was when I was a fellow, I had to do a project. We were seeing a lot of patients with Cushing’s — of course, that’s why I went there — and in those days we had no good imaging. There were no CT scans, no MRI, there was no way to image the pituitary gland to find out whether there was a tumor. By the late ’70s it became obvious that some patients with Cushing’s syndrome didn’t have pituitary tumors. They had tumors in their lungs and other places, and there was no good way of sorting these patients from the pituitary patients. My mentor at UCSF, Blake Tyrrell, MD, had the idea of sampling from the jugular vein to see if there was a gradient across the pituitary. I took the project up because I didn’t think this is going to be helpful due to there being too much venous admixture in the jugular vein from other sources of cerebral venous drainage. We went into the radiology suite to do the first patient. As I was sampling blood from the peripheral veins, the interventional radiologist, David Norman, MD, says, “Would you like to sample the inferior petrosal sinus?” I said, “Why not? It sounds like a good idea to me.” That turned out to be helpful. We then studied several patients, and it eventually went to publication. Now everybody acknowledges it is necessary, maybe not in all patients with Cushing’s, but in many patients with Cushing’s to separate pituitary from nonpituitary Cushing’s syndrome. __________ Official information Patient information from Canterbury Health Limited Endocrine Services INFERIOR PETROSAL SINUS SAMPLING WITH CRH STIMULATION Introduction You have been diagnosed with Cushing's syndrome which results from excessive production of the hormone cortisol, made by the adrenal glands. In your case, the adrenal glands are being driven by excessive amounts of another hormone called ACTH. This test is to determine where that ACTH is coming from. Constant high levels of ACTH are usually caused by a tumor. Approximately 80% of cases are tumors of the pituitary gland while the remainder may occur in the lung, pancreas and other sites (known as "ectopic" sites). This test relies on the fact that if the source of your high ACTH is the pituitary gland blood levels taken from very near the gland will be higher than the blood level in an arm vein. Pituitary gland tumors are often tiny and can't be seen even with the most modern scanners. This test will help your endocrinologist to know with almost 100% certainty whether the pituitary gland is the source or if a search is needed elsewhere (for example in the lungs or abdomen). This guides treatment, for example the recommendation for Pituitary surgery. Procedure You are allowed water only from midnight the night before (nothing else to eat or drink). You will be given a light sedative, but will be awake during the procedure. You will be taken to the Radiology Department where the procedure will take place. The radiologist will place some local anesthetic into the groin on each side over the main vein that drains blood from each leg. Then a fine bore catheter will be passed up the vein, past the heart and into the major vein in the neck (the jugular vein). From there it is passed into a smaller vein that drains blood directly from the pituitary gland, known as the inferior petrosal sinus. The procedure is repeated for the other side. X-ray screening guides the radiologist to know where the catheters are positioned. A small butterfly needle is inserted into an arm vein. Once the catheters are in place, blood samples will be taken from the right and left petrosal sinus, and an arm vein at exactly the same time. After two baseline samples, a hormone called CRH is injected into the arm vein. This increases ACTH when a pituitary gland tumor is present, but has no effect on ectopic ACTH production. Further blood samples are taken for another 10 to 15 minutes, then the catheters are withdrawn. Pressure is applied to the groins to minimize bruising. Often sampling is continued from the arm vein only, for a total of 90 minutes. You will have to remain lying on your back for at least 2 hours afterwards. Risks This procedure is very safe when performed by an experienced radiologist. Rarely, there have been reports of people having a stroke at the time of this procedure but this was related to a catheter of faulty design which is now no longer used. Bruising, which is common in Cushing's syndrome, may occur after the catheters are pulled out. Some people notice flushing of the face after the CRH and rarely it can result in a fall in blood pressure. From: http://www.pituitarycenter.com/html/article1.html INFERIOR PETROSAL SINUS SAMPLING Patients who are suspected of having a pituitary tumor resulting in Cushing's syndrome may be referred for inferior petrosal sinus sampling if findings on MRI examination of the pituitary did not reveal a tumor or are inconclusive. The inferior petrosal sinus sampling procedure is performed in the radiology department. With the patient on the angiography table both groin regions are partially shaved, sterilized, and a local anesthetic is injected into the skin to provide pain relief. A tiny incision is made within the skin and a needle is inserted to puncture the femoral vein which drains blood from the leg. A small catheter is then inserted into the vein and flushed with an intravenous solution. Longer catheters are passed into the shorter catheters and advanced through the large veins traversing the torso into the neck and then into the base of the skull. Thereafter, a microcatheter is advanced through each of these larger guiding catheters and threaded into the inferior petrosal sinuses which lie along the internal aspect of the skull base and drain blood from the pituitary gland. Once these microcatheters have been positioned, contrast dye is injected and X-rays are taken to verify their position in the inferior petrosal sinuses. Next, blood samples are collected from both catheters in the inferior petrosal sinuses and from a peripheral (usually arm) vein. Thereafter, corticotropin-releasing hormone is administered through the peripheral vein. Repeat blood samples are drawn 2, 5, and 10 minutes after the injection. Additional X-rays are taken to confirm that the catheters were not dislodged from their site during the sampling procedure. Thereafter, the catheters are removed and direct pressure is applied to the groin region to decrease the likelihood of bruising. Patients are observed for 4 hours following the procedure to ensure that no bleeding from the femoral vein puncture sites will occur. Normal non-strenuous activity may be resumed 48 hours after the procedure. Sedatives and pain relievers may be administered during the procedure as necessary. A blood thinner might be used depending on the patient's anatomy and the clinical suspicion of developing a blood clot. If a blood thinner is used, this may be counteracted with medication at the conclusion of the procedure to ensure that normal blood clotting resumes while removing the catheters. Overall, the inferior petrosal sinus sampling procedure involves minimal discomfort. The risks of the procedure are small. X-rays are used but the radiation doses are minimized. Infection is controlled by using sterile technique. Some patients might have an unexpected allergic reaction to the dye used during the study. A bruise may develop within the groin. Although rare, blood clots have developed in the groin veins following this procedure. Again, steps are taken to minimize the likelihood of each and every one of these complications. ACTH levels are measured in each of the blood samples obtained during the procedure. The ratios between the petrosal sinus sampling and the peripheral vein samples are compared. The results are used to determine whether ACTH production is due to either a pituitary or a non-pituitary source. ___ From: http://www.mc.vanderbilt.edu/pituitarycenter/html/article1.html Patients who are suspected of having a pituitary tumor resulting in Cushing's syndrome may be referred for inferior petrosal sinus sampling if findings on MRI examination of the pituitary did not reveal a tumor or are inconclusive. The inferior petrosal sinus sampling procedure is performed in the radiology department. With the patient on the angiography table both groin regions are partially shaved, sterilized, and a local anesthetic is injected into the skin to provide pain relief. A tiny incision is made within the skin and a needle is inserted to puncture the femoral vein which drains blood from the leg. A small catheter is then inserted into the vein and flushed with an intravenous solution. Longer catheters are passed into the shorter catheters and advanced through the large veins traversing the torso into the neck and then into the base of the skull. Thereafter, a microcatheter is advanced through each of these larger guiding catheters and threaded into the inferior petrosal sinuses which lie along the internal aspect of the skull base and drain blood from the pituitary gland. Once these microcatheters have been positioned, contrast dye is injected and X-rays are taken to verify their position in the inferior petrosal sinuses. Next, blood samples are collected from both catheters in the inferior petrosal sinuses and from a peripheral (usually arm) vein. Thereafter, corticotropin-releasing hormone is administered through the peripheral vein. Repeat blood samples are drawn 2, 5, and 10 minutes after the injection. Additional X-rays are taken to confirm that the catheters were not dislodged from their site during the sampling procedure. Thereafter, the catheters are removed and direct pressure is applied to the groin region to decrease the likelihood of bruising. Patients are observed for 4 hours following the procedure to ensure that no bleeding from the femoral vein puncture sites will occur. Normal non-strenuous activity may be resumed 48 hours after the procedure. Sedatives and pain relievers may be administered during the procedure as necessary. A blood thinner might be used depending on the patient's anatomy and the clinical suspicion of developing a blood clot. If a blood thinner is used, this may be counteracted with medication at the conclusion of the procedure to ensure that normal blood clotting resumes while removing the catheters. Overall, the inferior petrosal sinus sampling procedure involves minimal discomfort. The risks of the procedure are small. X-rays are used but the radiation doses are minimized. Infection is controlled by using sterile technique. Some patients might have an unexpected allergic reaction to the dye used during the study. A bruise may develop within the groin. Although rare, blood clots have developed in the groin veins following this procedure. Again, steps are taken to minimize the likelihood of each and every one of these complications. ACTH levels are measured in each of the blood samples obtained during the procedure. The ratios between the petrosal sinus sampling and the peripheral vein samples are compared. The results are used to determine whether ACTH production is due to either a pituitary or a non-pituitary source. ___ From https://www.uclahealth.org/radiology/interventional-neuroradiology/inferior-petrosal-sinus-sampling The IPSS test is done in some patients to identify if there is too much ACTH is causing the excess production of cortisol, and where it is coming from. How do we do an IPSS procedure? Typically under general anesthesia, we place small tubes (catheters) into the femoral veins (the main vein draining the legs) at the level of the groin. From there, under X-ray guidance, we navigate those catheters to the main veins which drain the Pituitary gland. These are the inferior petrosal sinuses (right and left). We then draw samples from those veins and the main vein of the abdomen and test those samples for ACTH. We also take timed samples after giving a dose of medication which would normally stimulate the production of ACTH to improve the sensitivity of the test. When we get the results, the different levels of ACTH may help the endocrinologist determine where the tumor is located that is causing the adrenal gland to produce the excess cortisol. If it is from the Pituitary gland, any difference between the right and left samples may help the surgeon determine the surgical plan to remove the tumor yet preserve the normal Pituitary gland. Example of testing results: Time Right IPS Left IPS Inf Vena Cava Cortisol Baseline 1 09:32 40 pg/ml 17 18 25 mcg/dl Baseline 2 09:34 45 18 15 24 DDAVP inj 09:38 Post 2min 09:40 72 21 18 Post 5min 09:43 157 20 19 Post 10min 09:48 161 30 25 Post 15min 09:53 162 33 26 Post 30min 10:08 124 32 29 30 This example shows elevation of ACTH in the right inferior petrosal sinus, likely indicating a tumor in the right side of the pituitary gland causing Cushing’s Disease. Picture of contrast injection of the inferior petrosal sinuses: Tips of the catheters in the inferior petrosal sinuses.

Dr. Irmanie Hemphill, who first thought her weight gain was due to having a baby. Doctors at Cleveland Clinic Florida in Weston diagnosed her with a tumor in the pituitary gland in her brain. In the summer of 2019, Irmanie Hemphill gained a lot of weight, developed acne and had high blood pressure. She attributed it to her body adjusting from giving birth just six weeks prior. “I was thinking maybe it was just hormonal changes from having a baby,” said Hemphill, 38, of Pembroke Pines. But when Hemphill, a family medicine physician, saw that her nails were turning dark and she gained five pounds within a week, she knew it was something more serious. Blood tests ordered by her physician came back normal, with the exception of high levels of cortisol detected via a urine cortisol test, which she requested after researching her symptoms online. The next step was to find out where the excess cortisol was coming from: either her kidneys or her adrenal glands, which produce hormones in response to signals from the pituitary gland in the brain. The first MRI of her brain did not detect anything abnormal, so her endocrinologist attributed her symptoms to her body adjusting post-pregnancy. Hemphill sought a second opinion at Cleveland Clinic Weston, where more MRIs of her brain, combined with an Inferior Petrosal Sinus Sampling (IPSS) procedure, detected she had a tumor on her pituitary gland. That led her to be diagnosed with Cushing’s Disease — caused by excess cortisol. TWO TYPES OF PITUITARY TUMORS There are two types of pituitary tumors: those that produce active hormones, like the one Hemphill had, and those that do not, which grow in size over time and do not manifest symptoms right away. Hemphill’s tumor was producing adrenocorticotropic hormone (ACTH), which causes the adrenal gland to produce more cortisol. Many people with Cushing’s Disease experience high blood pressure and high blood sugar, muscle fatigue, easy bruising and brain fog. If left untreated, the condition can lead to pulmonary embolisms, diabetes, osteoporosis, strokes and heart attacks. “It was a little bit of relief but also sadness,” said Hemphill, of finding out her diagnosis. “I was very happy that I got a diagnosis but now it’s like, what’s the next step?” LESS INVASIVE WAY TO REMOVE A PITUITARY TUMOR Hospitals in South Florida are at the forefront in developing new research, techniques and technologies for pituitary tumors. The tiny bean-shaped pituitary gland is located at the base of the brain and controls many of the body’s hormonal and metabolic functions. Last June, neurosurgeon Dr. Hamid Borghei-Razavi of Cleveland Clinic Weston removed Hemphill’s pituitary tumor through her nose. This type of procedure allows surgeons to remove the tumor without damaging the brain. “It’s a less-invasive approach compared to 20 years ago, when pituitary tumors were removed through the cranium,” he said. “Now, with new technologies, more than 95% of pituitary tumors can be removed through the nose.” The procedure takes just a few hours to complete, based on the size and location of the tumor. Patients usually stay at the hospital for one to two days afterward for observation. The removal of Hemphill’s tumor, which was three to four millimeters in size, put an end to her Cushing’s Disease and her symptoms, though it took six months to a year for Hemphill to feel normal. (She was prescribed cortisol for six months until her adrenal glands could restart producing cortisol on their own.) “Sometimes it’s very hard to make a diagnosis for pituitary tumors because we don’t see them in the MRIs,” said Borghei-Razavi. “We call it MRI Negative Cushing’s Syndrome. It means we don’t see it in the MRI, but the cells are there,” he said. Borghei-Razavi and Hemphill credit the Inferior Petrosal Sinus Sampling (IPSS) test as pinpointing her tumor. Cleveland Clinic Weston is among only a handful of medical practices in South Florida that use this technique. Three Ways to Remove the Tumor Most pituitary tumors are benign. The challenge is when it comes to removing the tumor. “Pituitary tumors come in all shapes and sizes,” says Dr. Zoukaa Sargi, a head and neck surgeon at Sylvester Comprehensive Cancer Center at the University of Miami. “There are non-functional tumors that do not secrete hormones that can reach extreme sizes of up to 10 centimeters before coming to medical attention. This is the equivalent of the size of a grapefruit,” he says. “Then there are functional tumors that produce hormones that are typically discovered much sooner and can be only a few millimeters in size before coming to medical attention. A small proportion, less than 1%, are malignant,” he adds. There are three treatment options for pituitary tumors: surgical removal, medical therapy and radiation. “Medical therapy is only applicable in certain functional tumors that produce hormones,” says Dr. Ricardo Komotar, a neurosurgeon who is director of the Sylvester Comprehensive Cancer Center Brain Tumor Initiative. “Radiation is an option primarily for inoperable tumors with high surgical risk. Surgical removal is the optimal treatment in the vast majority of pituitary cases, conferring the greatest benefit with the lowest morbidity,” he says. Dr. Rupesh Kotecha, chief of radiosurgery at Miami Cancer Institute (MCI), part of Baptist Health South Florida, says there are a number of different hormones that the pituitary gland can secrete. “Prolactin is the most common form of pituitary adenoma that’s functioning and accounts for 30% to 50%,” he said. Excess prolactin can cause the production of breast milk in men and in women who are not pregnant or breastfeeding. Kotecha said the next most common are growth-hormone secreting tumors, which occur in 10% of patients. ACTH-secreting adenomas — the kind that Hemphill had — account for 5% of patients, while 1% secrete TSH, which causes the thyroid gland to be overactive. MCI’s Proton Therapy delivers high-dose radiation that treats the tumor’s area, allowing for surrounding tissues and organs to be spared from the effects of radiation. “The pituitary gland essentially sits in the middle of the brain,” says Kotecha. “It’s sitting in the middle of all of these critical structures.” From https://www.miamiherald.com/living/health-fitness/article251653033.html

Minimally invasive diagnostic methods and transnasal surgery may lead to remission in nearly all children with Cushing’s disease, while avoiding more aggressive approaches such as radiation or removal of the adrenal glands, a study shows. The study, “A personal series of 100 children operated for Cushing’s disease (CD): optimizing minimally invasive diagnosis and transnasal surgery to achieve nearly 100% remission including reoperations,” was published in the Journal of Pediatric Endocrinology and Metabolism. Normally, the pituitary produces adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands to produce cortisol. When a patient has a pituitary tumor, that indirectly leads to high levels of cortisol, leading to development of Cushing’s disease (CD). In transnasal surgery (TNS), a surgeon goes through the nose using an endoscope to remove a pituitary tumor. The approach is the first-choice treatment for children with Cushing’s disease due to ACTH-secreting adenomas — or tumors — in the pituitary gland. Micro-adenomas, defined as less than 4 mm, are more common in children and need surgical expertise for removal. It is necessary to determine the exact location of the tumor before conducting the surgery. Additionally, many surgeons perform radiotherapy or bilateral adrenalectomy (removal of both adrenal glands) after the surgery. However, these options are not ideal as they can be detrimental to children who need to re-establish normal growth and development patterns. Dieter K. Lüdecke, a surgeon from Germany’s University of Hamburg, has been able to achieve nearly 100% remission while minimizing the need for pituitary radiation or bilateral adrenalectomy. In this study, researchers looked at how these high remission rates can be achieved while minimizing radiotherapy or bilateral adrenalectomy. Researchers analyzed 100 patients with pediatric CD who had been referred to Lüdecke for surgery from 1980-2009. Data was published in two separate series — series 1, which covers patients from 1980-1995, and series 2, which covers 1996-2009. All the surgeries employed direct TNS. Diagnostic methods for CD have improved significantly over the past 30 years. Advanced endocrine diagnostic investigations, such as testing for levels of salivary cortisol in the late evening and cortisol-releasing hormone tests, have made a diagnosis of CD less invasive. This is particularly important for excluding children with obesity alone from children with obesity and CD. Methods to determine the precise location of micro-adenomas have also improved. The initial methodology to localize tumors was known as inferior petrosal sinus sampling (IPSS), an invasive procedure in which ACTH levels are sampled from the veins that drain the pituitary gland. In series 1, IPSS was performed in 24% of patients, among which 46% were found to have the wrong tumor location. Therefore, IPSS was deemed invasive, risky, and unreliable for this purpose. All adenomas were removed with extensive pituitary exploration. Two patients in series 1 underwent early repeat surgery; all were successful. Lüdecke introduced intraoperative cavernous sinus sampling (CSS), an improved way to predict location of adenomas. This was found to be very helpful in highly select cases and could also be done preoperatively for very small adenomas. In series 2, CSS was used in only 15% of patients thanks to improved MRI and endocrinology tests. All patients who underwent CSS had correct localization of their tumors, indicating its superiority over IPSS. In series 2, three patients underwent repeat TNS, which was successful. In these recurrences, TNS minimized the need for irradiation. The side effects of TNS were minimal. Recurrence rate in series 1 was 16% and 11% in series 2. While Lüdecke’s patients achieved a remission rate of 98%, other studies show cure rates of 45-69%. Only 4% of patients in these two series received radiation therapy. “Minimally invasive unilateral, microsurgical TNS is important functionally for both the nose and pituitary,” the researchers concluded. “Including early re-operations, a 98% remission rate could be achieved and the high risk of pituitary function loss with radiotherapy could be avoided.” From https://cushingsdiseasenews.com/2018/09/04/minimally-invasive-methods-yield-high-remission-in-cushings-disease-children/

By: SHERRY BOSCHERT, Family Practice News Digital Network SAN FRANCISCO – The size of a pituitary tumor on magnetic resonance imaging in a patient with ACTH-dependent Cushing’s syndrome can’t differentiate between etiologies, but combining that information with biochemical test results could help avoid costly and difficult inferior petrosal sinus sampling in some patients, a study of 131 cases suggests. If MRI shows a pituitary tumor larger than 6 mm in size, the finding is 40% sensitive and 96% specific for a diagnosis of Cushing’s disease as the cause of adrenocorticotropic hormone (ACTH)-dependent Cushing’s syndrome, and additional information from biochemical testing may help further differentiate this from ectopic ACTH secretion, Dr. Divya Yogi-Morren and her associates reported at the Endocrine Society’s Annual Meeting. Pituitary tumors were seen on MRI in 6 of 26 patients with ectopic ACTH secretion (23%) and 73 of 105 patients with Cushing’s disease (69%), with mean measurements of 4.5 mm in the ectopic ACTH secretion group and 8 mm in the Cushing’s disease group. All but one tumor in the ectopic ACTH secretion group were 6 mm or smaller in diameter, but one was 14 mm. Because pituitary "incidentalomas" as large as 14 mm can be seen in patients with ectopic ACTH secretion, the presence of a pituitary tumor can’t definitively discriminate between ectopic ACTH secretion and Cushing’s disease, said Dr. Yogi-Morren, a fellow at the Cleveland Clinic. That finding contradicts part of a 2003 consensus statement that said the presence of a focal pituitary lesion larger than 6 mm on MRI could provide a definitive diagnosis of Cushing’s disease, with no further evaluation needed in patients who have a classic clinical presentation and dynamic biochemical testing results that are compatible with a pituitary etiology (J. Clin. Endocrinol. Metab. 2003;88:5593-602). The 6-mm cutoff, said Dr. Yogi-Morren, came from an earlier study reporting that 10% of 100 normal, healthy adults had focal pituitary abnormalities on MRI ranging from 3 to 6 mm in diameter that were consistent with a diagnosis of asymptomatic pituitary adenomas (Ann. Intern. Med. 1994;120:817-20). A traditional workup of a patient with ACTH-dependent Cushing’s syndrome might include a clinical history, biochemical testing, neuroimaging, and an inferior petrosal sinus sampling (IPSS). Biochemical testing typically includes tests for hypokalemia, measurement of cortisol and ACTH levels, a high-dose dexamethasone suppression test, and a corticotropin-releasing hormone (CRH) stimulation test. Although IPSS is the gold standard for differentiating between the two etiologies, it is expensive and technically difficult, especially in institutions that don’t regularly do the procedure, so it would be desirable to avoid IPSS if it’s not needed in a subset of patients, Dr. Yogi-Morren said. The investigators reviewed charts from two centers (the Cleveland Clinic and the M.D. Anderson Cancer Center, Houston) for patients with ACTH-dependent Cushing’s syndrome seen during 2000-2012. ACTH levels were significantly different between groups, averaging 162 pg/mL (range, 58-671 pg/mL) in patients with ectopic ACTH secretion, compared with a mean 71 pg/mL in patients with Cushing’s disease (range, 16-209 pg/mL), she reported. Although there was some overlap between groups in the range of ACTH levels, all patients with an ACTH level higher than 210 pg/mL had ectopic ACTH secretion. Median serum potassium levels at baseline were 2.9 mmol/L in the ectopic ACTH secretion group and 3.8 mmol/L in the Cushing’s disease group, a significant difference. Again, there was some overlap between groups in the range of potassium levels, but all patients with a baseline potassium level lower than 2.7 mmol/L had ectopic ACTH secretion, she said. Among patients who underwent a high-dose dexamethasone suppression test, cortisol levels decreased by less than 50% in 88% of patients with ectopic ACTH secretion and in 26% of patients with Cushing’s disease. Most patients did not undergo a standardized, formal CRH stimulation test, so investigators extracted the ACTH response to CRH in peripheral plasma during the IPSS test. As expected, they found a significantly higher percent increase in ACTH in response to CRH during IPSS in the Cushing’s disease group, ranging up to more than a 1,000% increase. In the ectopic ACTH secretion group, 40% of patients did have an ACTH increase greater than 50%, ranging as high as a 200%-300% increase in ACTH in a couple of patients. "Although there was some overlap in the biochemical testing, it is possible that it provides some additional proof to differentiate between ectopic ACTH secretion and Cushing’s disease," Dr. Yogi-Morren said. In the ectopic ACTH secretion group, the source of the secretion remained occult in seven patients. The most common identifiable cause was a bronchial carcinoid tumor, in six patients. Three patients each had small cell lung cancer, a thymic carcinoid tumor, or a pancreatic neuroendocrine tumor. One patient each had a bladder neuroendocrine tumor, ovarian endometrioid cancer, medullary thyroid cancer, or a metastatic neuroendocrine tumor from an unknown primary cancer. The ectopic ACTH secretion group had a median age of 41 years and was 63% female. The Cushing’s disease group had a median age of 46 years and was 76% female. Dr. Yogi-Morren reported having no financial disclosures. sboschert@frontlinemedcom.com On Twitter @sherryboschert From Famiiy Practice News