Carcinoid tumor of the pancreas causing the diarrheogenic syndrome: report of a case combined with multiple endocrine neoplasia, type I.

A case of carcinoid tumor of the pancreas with the watery diarrhea, hypokalemia, and hypochlorhydria syndrome in association with hyperparathyroidism and the amenorrhea-galactorrhea syndrome is presented. Resection of the three grossly enlarged, hyperplastic parathyroid glands restored eucalcemia in this patient. A subsequent excision of the 370 gm pancreatic carcinoid tumor resulted in a cure of the watery diarrhea and a return of the gastric acid secretion to normal. Immunocytochemical studies of the pancreatic tumor demonstrated a positive stain only for serotonin, and negative results for vasoactive intestinal polypeptide, pancreatic polypeptide, glucagon, insulin, cholecystokinin, gastrin, and calcitonin were obtained. These studies suggest that in this patient, serotonin was a causative agent of the watery diarrhea syndrome.