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False-positive inferior petrosal sinus sampling in the diagnosis of Cushing's disease


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Thank you SOOOO much for posting this article.


Since my IPSS results in November, I have done a bit of research on IPSSes and false positives. The MD Anderson endiot was telling me that my IPSS didn't prove Cushing's because I didn't have a high UFC or the proper response to the stim and suppress tests. I chewed her out over it and told her I totally disagreed.


I hate those little seeds of doubt that these doctors can plant. I have been wondering... is it possible I am a false positive, too?


This article gave me the information that I needed. WHY? WIth just two cases? Yes.


I looked at the results from those poor soul's IPSSes. Those results were not very high compared to mine. I think their highest value was 820. My values on the right ranged from 1500 to 3440. (see full signature to prevent lots of scrolling :))


This, combines with my other findings, makes me feel very confident I am not a false positive.


This article below contains a review of the literature for 20 years about the IPSS results and specificity and false positives and negatives.


I learned that false negatives are a lot more common that false positives. And there is a chart in that article showing all the numbers. Although they didn't tally them up, I did. I found that out of over 1,700 successfull IPSS procedures, only SEVEN were false positives. SEVEN. That is less than one percent, or 0.58% when I calculated it with the real totals (i don't hav eit in front of me now). Then, I see an article showing TWO of those seven and compared their numbers....


I have officially check out of this doubt game over this disease. I am not a false positive IPSS result. I do have Cushing's, and soon, I will be done with all this! :)





Diagnostic Errors after Inferior Petrosal Sinus Sampling



Neuroendocrine Clinical Center (B.S., L.K., K.M., S.G., A.K., B.M.K.B.), Division of Neurosurgery (B.S.), Biostatistics Center

(D.J.D.), and Department of Radiology (A.W.), Massachusetts General Hospital, Boston, Massachusetts 02114

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It was the MDA endiot who made me look for this stuff. She ( Busaidy) told me that my IPSS didn't count because my baselines were all immeasureable( <5 L,R, P). Also that my UFC was not high.


So NOW after surgery, I am doubting my results. I am completely off cortef as of Thursday last week. My last serum cortisol was 15 and ACTH was 23 at 8am after withholding. My blood pressure is higher than before surgery (ave. 145/94 )some striae are dark again too.

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I thought this was good:


In the two patients reported here, the results of IPSS suggested a pituitary origin of ACTH secretion, but transsphenoidal surgery failed to disclose a pituitary adenoma or to improve postoperative plasma cortisol levels. Both patients subsequently were found to have an ACTH-secreting carcinoid tumor of the lung. The false-positive IPSS studies were due to periodic hormonogenesis, and we therefore conclude that the patient must be hypercortisolemic at the time IPSS is performed for the study to be valid.



AND ...



The first patient didn't even have a pituitary MRI!!!


A computerized tomography (CT) scan of the head showed a possible microadenoma on the left side of the pituitary gland.




A magnetic resonance (MR) image was not obtained because of the patient?s claustrophobia. A CT scan of the chest showed a 1-cm indeterminate nodule in the right midlung (Fig. 2).







Inferior petrosal sinus sampling showed no baseline IPS/P gradient, but a significant gradient (12:1) was found with oCRH in the left IPS (Table 2). Both CT scans and MR images failed to show evidence of a pituitary lesion.


If the authors think that 12 to 1 is SIGNIFICANT, what would they say to 93 to 1? That's what I had!!!!!


The patient subsequently developed necrotizing Aspergillus bronchopneumonia and died 3 months after surgery. The postmortem study revealed a 1-cm bronchial

carcinoid tumor in the posterior segment of the right upper lung. and then later


Recent advances in assay techniques and their wide availability make it possible to diagnose Cushing?s syndrome earlier in the natural history of the illness, possibly when the clinical signs are subtle and disabilities less severe. A potential problem in diagnosing ACTH-dependent Cushing?s syndrome is the cyclic or intermittent activity of the disease seen in some patients.1


Seems like we need to ALL be getting a CT scan to make sure that it is not ectopic ACTH syndrome where it shows up on the lungs. I have an appt with my local endo on 12/20 and my neurosurgeon on 12/18 and I will get one of them to order it.


Jeremie and I have been strongly questioning doctors on the posibility that our Cushing's could be ectopic. High ACTH and high Cortisol can be either pituitary Cushing's disease or ectopic ACTH syndrome. We have been wondering why people dont' get chest x-rays.


I think of it like this: if the pituitary is the source of 70% of Cushing's patients and we get a pituitary MRI, then why don't those with high ACTH and high cortisol get a chest CT, since ectopic ACTH syndrome shows up in the chest as a malignant carcinoid in something like 60-70% of the cases, right?!


I will be sure to point Jeremie to this post. This topic has driven us CRAZY over the months!


I have to get my chest CT before the end of the year while it is still "free."


Hugs to all for making it through this post :)


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There is another female endiot there at MDA.


(don't say the name people. I know her name. I am trying not to post it, so please don't out me by posting the real name in a post below mine. that has happened a few times before.)

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Hi All! I wanted to add that one other thing that points to an ectopic source is the failure to respond to the Dex?CRH test that many of us had in Seattle. From the diagnostic protocols I've found- when a patient has high ACTH and does not respond, ectopic Cushings should be suspected. Dr. L refused to entertain this possibility and told me to go to my PCP if I had other concerns. WHat kind of Dr. does that? Typically they at least tell you that you need to go or whom to see. I'm glad you are both getting chest X-rays.


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I've wondered about an ectopic source. I have what has shown up for years on xrays as "granulomatous disease" as well as sclerosing adenosis in my breasts. Obviously, I've got a lot of things going on. I've considered going to possibly a geneticist or something, but honestly I'm at a loss as to how to proceed. Hoping the endo I see in January will be open enough to be able to point me in a good direction so I stop all this floundering.

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I can't bear to read the article right now. I see the doctor tomorrow.


What I don't understand is that with infants when there are signs of rare problems or such genetics specialists are brought in and they do testing to see if there are markers for other problems so that they can find them and do something. I've often wondered if genetic testing might not be of use to me. Why is it we have to keep guessing just because we can say "doctor it hurts"... oh I don't know. I'm tired. Maybe that's clouding my judgment.

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I wanted to say a few things. How have you been feeling after surgery? Since you wonder about ectopic source, I was wondering if your symptoms have returned? I hope not.

You mentioned the CRH/DEX test and people not responding with an ectopic source. My opinion is that this test isn't all that useful anyhow. Many people have been cured of pit. Cushing's but they did fail that test. They didn't have an ectopic source but they did fail the CRH/DEX test. I just think that test isn't all that helpful period. I do think it is interesting that people do not see a rise with ectopic source and that test. Maybe people should be having CT SCans to be certain before surgery.

Phil, I hope you get some answers soon. I truly hope that you have a cure. I know that you have your doubts and I hope the doctors can figure this out soon for you.

Kate G

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This is all very interesting! First of all, the doubt. Why do we or will we always have that little bad voice in the back of our brains saying "but what if it isn't / wasn't cushings"? I know, I know, because so many doctors have beat it in our heads that there is no way we could possible have or had cushings.


Secondly, the etopic source . . . . . cause you see after two pit surgeries and a BLA I've now been told that I have a "spot" on my lung. Based on my "endocrine" symptoms I really don't think it is an ACTH producing "spot" but there's that "wonder" and "doubt" . . . . . did we really get it right? Yes, we did . . . . . BUT . . . . what the heck is this spot?


I was one of the ones who had very high ACTH numbers during my CSS (IPSS). My right side went to over 20,000. For some reason that really removed doubt from my mind.


Too early in the morning for me to be thinking so hard . . . . . . :D

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From what I understand fromt he info Dr Snyder gave me - if the octreo scan lights up the lung tumor, then it must be ACTH.


ONE MROI showed something on my sisters pituitary. a "mass" But the neurosurgeons could not find anything. the PSS testing showed that it must not be pituitary. I can tell you it is definately VERY advanced Cushing's.


Her Cortisol nubers were off the charts. over 800. I understand that kind of points to ectopic as well.


The octreoscan lit my sisters lung tumor up like a lightbulb. The chemical attacces itself tot he the hormone, and lights up in the scan. He saw it light up some other areas but said it was normal for the hormone to be in those areas. So he is sure that the lung tumor is the culprit.


This morning I pleaded with him. I said whatif the PSS test was wrong and we are doing this lung surgery and dosing her up with cortisol after and there is another source. He said that real risk here is not having the surgery. That lung tumor has got to be the problem. It's got to come out.


I'm very thankful to Dr Kyser who was able to get my sister in to surgery so quicky. We met him on Friday and he operates on Wed!

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Well I pretty much feel that I do still have Cushing's. I also trust that Dr. McC was very thorough when he removed the tumors from my pit. Unless the tumor has returned, there must be another source.

When Dr. D gave my IPSS report he noted that it was difficult to interpret, as the baselines were all immeasurable. Dr. Busaidy was concerned about this too.

5 days without cortef, dark striae, acne, 5lbs weight gain since surgery.

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I am so so so sorry that you are experiencing symptoms and feel like you still have Cushings. One thing I wanted to mention is that sometimes additional tumor can be lurking in places that are not visible during surgery. It is so frustrating, and I'm so sorry.


Have you done any cortisol testing yet or gotten a post-op MRI?


We're here to help as you face whatever may be next.


Lots of hugs,


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