Whenever a new imaging method is used widely, incidental findings from it are encountered. The new Ga-68 DOTATATE PET is no exception. It is well known that DOTATATE signals are normally found in the pituitary, salivary glands, thyroid, liver, spleen, and adrenal glands. Some people may also have signals in the pancreas.
Although the adrenal glands are known to be lit up by DOTATATE PET, the signal from normal adrenal glands is usually low. A technical jargon called the standard uptake value (SUV) quantitatively describes the intensity of PET signals. Unfortunately, different machines give out different SUVs on the same organ of the same patient. The SUV thus has relative importance only in the same patient using the same machine.
I saw a patient recently. She had another kind of neuroendocrine tumor and did a DOTATATE PET. The PET showed she had strong signal on one adrenal gland (SUV ~8) while the other adrenal gland had normal signal (SUV ~2). CT showed a tiny nodule in the adrenal gland with strong PET signal. Is this a metastatic lesion of the other neuroendocrine tumor? Or is it a tiny pheo that is incidentally found by the DOATATE PET? Either adrenal metastasis from neuroendocrine tumor or pheo is rare. Based on a variety of factors, I favor she has a tiny pheo. There are no convincing ways to prove either diagnosis. Only time will tell.
Dr. Pheo
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Dr. Pheo, sorry if this is a duplicate but I’m not sure if my previous comment went through.
ReplyDeleteI am wondering if my symptoms sound like pheochromocytoma to you. I have had bp around 130/85 for a few years now but this past April I started having heart palpitations and noticed my bp was closer to 140/90, then I started not feeling good at all the day after a run. Typically I was running 30-50 miles a week, I’m done to 0 now because I’m tired and every time I even walk a couple miles the next day I feel horrible with an increased heart rate. I actually ended up in the ER once and my blood pressure was high, 150/100 up to 199/115. Since the ER I’ve been on losartan and the BP has stayed under 140/90 except occasionally. But my heart rate is still a lot higher than usual and it increases quickly when standing and walking. Walking slowly upstairs can raise it to over 130 bpm. I am waiting results on a metanephrine fractionated urine test (not the 24 hour one). Thank you for your time.
Dear Brian,
DeleteThe symptoms are suggestive of pheo. You should test plasma metanephrines.
Dr. Pheo
test
ReplyDeleteI had a Pheochromocytoma 30 years ago. My right adrenal gland is removed together with the 6 cm large tumor. Second Pheo (recurrence) removed 3,5 years ago (same location where my right adrenal gland has been removed. No mutations found.
ReplyDeleteNow, during my annual check-up, an increase in metanephrine was found in my
2 x 24 -hour urine metanephrines:
Methanefrine /kreatine: 107 and 127 (normal tot 70 nmol/l)
Is this increase something that I have to worry about? I now have plasma fractionated metanephrines punctured. I do not have a result yet. If the reslut of plasma metanefrines is between the reference values, is that sufficient proof that nothing is wrong? Is there a reason to be concerned at this point? How would you move forward?
Is it possible that the increase in urine is a result of stress?
Thank you for your time.
Dear Anonymous,
DeleteAs you had the first pheo as a young person and you already had a recurrence, any positive pheo test results should be treated seriously. You can repeat the tests over the next several months. If the abnormal results are due to stress, some test results will be lower or normal. If they are persistently elevated, you need imaging to search for the tumor.
Dr. Pheo
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ReplyDeleteHello Dr Pheo,
ReplyDeleteI am currently going through testing for possible pheochromocytoma and have had uterine fibroids for the past 7 years. Is there any correlation between the two? Do you find that your pheo patients tend to also have tumors that grow elsewhere.
Dear Unknown,
DeleteThere is no link between pheo and uterine fibroids. In patients with genetic pheo syndromes, pheo is associated with medullary thyroid cancer, parathyroid tumor, renal cell cancer, and other tumors.
Dr. Pheo
Dear Dr Pheo,
ReplyDeleteMy question is about MIBG and PET-CT DOTA scans.
Do I need one? If I have a choice, which one of the two should I get?
BACKGROUND
I'm 43. No known maladies in my past. No family history of endocrine issues or Pheo.
Just before Christmas I had two excruciating lightening headaches in a few days. They abated in about 30 minutes. Local doctor said blood pressure was a little high but nothing to worry about.
48 hours later I was in an ambulance due to a hypertensive crisis (cataclysmic headache that persisted, blood pressure over 230). After a week or so in hospital doing tests, hospital doctors ordered pheo tests. Urinary free metanephrine levels came up roughly 6 times the reference intervals. CT scan soon after showed 3.6cm tumor on one adrenal gland.
Doctors ordered MIBG scan in anticipation of future surgery and put me on phenoxybenzamine, propranolol and amlodypine. Then finally discharged me.
The wait for MIBG was 2 months. Then another month to see a doc about results.
Sadly the MIBG scan showed negative (not even the tumor from the CT was visible). I didn't stop taking medications for the MIBG scan and I'm told that propranolol may inhibit MIBG uptake so perhaps that's why.
I don't have private health insurance. The public system here in Hong Kong is excellent but involves long wait times. Taking so much phenoxybenzamine makes me tired all the time and limits my ability to do focused work for the hours I need to. I'd like to get surgery as quickly as possible. But I also don't want to rush if more imaging evidence would indicate different interventions.
Scan facts
• To get another MIBG in public system would mean another 3-4 month's delay.
• PET-CT DOTA scan is not available in the public system here but four private hospitals can do it.
• MIBG is also available privately.
• Both scans cost about US$2,200 privately (quite a bit for me).
QUESTIONS
1) Are more scans likely to provide much benefit on top of the CT and urinary test?
2) If yes, is PET-CT DOTA or a retry of MIBG better in my case?
3) For PET-CT DOTA, one of the or private hospitals that I asked said "For pheochromocytoma, an additional FDG PET/CT scan may be required". Is it? Why/why not?
4) Also for PET-CT in my case does it need to be a whole body scan?
I guess the final question is about timing in general. Is it bad to be taking phenoxybenzamine months longer than absolutely necessary? Is delaying surgery for months worth it for an MIBG retry?
Any general thoughts would be much appreciated.
Dear Dallas,
ReplyDeleteThe imaging features of the adrenal tumor on CT are very important. If the adrenal tumor has features consistent with pheochromocytoma, you don't need MIBG scan or DOTATATE PET. IF the adrenal tumor doesn't have features of pheochromocytoma, you can do an FDG PET if it is less expensive or covered. Another option is CT of chest and pelvis, if covered.
Dr. Pheo
It is very generous of you to respond, thank you!
ReplyDeleteDoes failure of MIBG to show the 3.5cm adrenal tumor make it any less likely to be a Pheo? Or is the MIBG result meaningless on that score?
The doctor had described the contrast CT result as most likely a benign Pheo so I hope the imaging features are consistent with that... but I'll dig for more details next chance I get!
They seem to do MIBG as standard practice here (CT & MIBG bookings both got underway as soon as metanephrine tests were repeated)... so MIBG wasn't a special order made on basis of CT imaging. But I had to wait months for it.
Would investing in a PET-DOTA scan for peace of mind be silly? I mean, even if indications were Pheo, just to rule out other low-probability alternatives and maybe give the specialists more data?
Dear Dallas,
ReplyDeleteThe DOTATATE PET would be reassuring.
Dr. Pheo
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ReplyDelete