A VIPoma (also known as Verner–Morrison syndrome, after the physicians who first described it) is a rare (1 per 10,000,000 per year) endocrine tumor, usually (about 90%) originating from non-β islet cell of the pancreas, that produce vasoactive intestinal peptide (VIP). It may be associated with multiple endocrine neoplasia type 1.
The massive amounts of VIP in turn cause profound and chronic watery diarrhea and resultant dehydration, hypokalemia, achlorhydria (hence WDHA-syndrome, or pancreatic cholera syndrome), acidosis, vasodilation (flushing and hypotension), hypercalcemia and hyperglycemia.
Symptoms and signsEdit
The major clinical features are prolonged watery diarrhea (fasting stool volume > 750 to 1000 mL/day) and symptoms of hypokalemia and dehydration. Half of the patients have relatively constant diarrhea while the rest have alternating periods of severe and moderate diarrhea. One third have diarrhea < 1yr before diagnosis, but in 25%, diarrhea is present for 5 yr or more before diagnosis. Lethargy, muscle weakness, nausea, vomiting and crampy abdominal pain are frequent symptoms. Hypokalemia and impaired glucose tolerance occur in < 50% of patients. Achlorhydria is also a feature. During attacks of diarrhea, flushing similar to the carcinoid syndrome occur rarely.
Besides the clinical picture, fasting VIP plasma level may confirm the diagnosis, and CT scan and somatostatin receptor scintigraphy are used to localise the tumor, which is usually metastatic at presentation.
- Blood chemistry tests (basic or comprehensive metabolic panel)
- CT scan of the abdomen
- MRI of the abdomen
- Stool examination for cause of diarrhea and electrolyte levels
- Vasoactive intestinal peptide (VIP) level in the blood
The first goal of treatment is to correct dehydration. Fluids are often given through a vein (intravenous fluids) to replace fluids lost in diarrhea.
The next goal is to slow the diarrhea. Some medications can help control diarrhea. Octreotide, which is a human-made form of the natural hormone somatostatin, blocks the action of VIP.
The best chance for a cure is surgery to remove the tumor. If the tumor has not spread to other organs, surgery can often cure the condition.
For metastatic disease, peptide receptor radionuclide therapy (PRRT) can be highly effective. This treatment involves attaching a radionuclide (Lutetium-177 or Yttrium-90) to a somatostatin analogue (octreotate or octreotide). This is a novel way to deliver high doses of beta radiation to kill tumours.
Some people seem to respond to a combination chemo called capecitabine and temozolomide but there is no report that it totally cured people from vipoma.
Surgery can usually cure VIPomas. However, in one-third to one-half of patients, the tumor has spread by the time of diagnosis and cannot be cured.
- Verner JV, Morrison AB (Sep 1958). "Islet cell tumor and a syndrome of refractory watery diarrhea and hypokalemia". Am J Med. 25 (3): 374–80. doi:10.1016/0002-9343(58)90075-5. PMID 13571250.
- "VIPoma" at Dorland's Medical Dictionary
- Mansour JC, Chen H (Jul 2004). "Pancreatic endocrine tumors". J Surg Res. 120 (1): 139–61. doi:10.1016/j.jss.2003.12.007. PMID 15172200.
- "VIPoma | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Retrieved 2018-04-17.
- Jensen RT, Norton JA. Endocrine tumors of the pancreas and gastrointestinal tract. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease . 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 32.
- National Cancer Institute. Islet cell tumors (pancreatic) treatment PDQ. Updated October 31, 2008.