A pancreatic neuroendocrine tumor presents with watery diarrhea and facial flushing. This description is most consistent with which tumor?

• A. VIPoma
• B. Insulinoma
• C. Glucagonoma
• D. Somatostatinoma

Answer: (A)

This presentation points to a VIP-secreting pancreatic neuroendocrine tumor. Vasoactive intestinal peptide (VIP) stimulates intestinal water and electrolyte secretion, leading to profuse, watery diarrhea. VIP also causes vasodilation, which explains the facial flushing. Together, these features are classic for a VIPoma, and the syndrome often includes hypokalemia and achlorhydria (the WDHA triad: watery diarrhea, hypokalemia, achlorhydria), though you may only see diarrhea and flushing highlighted in the stem.

Understanding the other pancreatic neuroendocrine tumors helps solidify why they’re less likely: insulinoma causes hypoglycemia with neuroglycopenic symptoms rather than profuse diarrhea; glucagonoma typically presents with weight loss, anemia, and a characteristic rash (necrolytic migratory erythema) plus hyperglycemia; somatostatinoma can cause diabetes and steatorrhea. The combination of watery diarrhea and flushing without those other syndrome features best fits a VIPoma.