Watery diarrhea syndrome due to an adrenal pheochromocytoma secreting vasoactive intestinal polypeptide

A 55-year-old woman presented with several protracted episodes of diarrhea; it was found to be secretory in origin. In the course of evaluating the diarrhea, an ultrasound of the abdomen was performed which disclosed a large right adrenal mass. Endocrinologic studies revealed elevated serum levels of gastrin, vasoactive intestinal polypeptide (VIP), catecholamines, and its metabolites. Surgery was performed successfully without any intraoperative complications, and postoperatively the patient was asymptomatic without further episodes of diarrhea. Histologically the tumor was a pheochromocytoma with neuroendocrine granules of vasoactive intestinal polypeptide and norepinephrine. To our knowledge, there have been six previously reported cases of pheochromocytoma secreting vasoactive intestinal polypeptide. In a patient with secretory diarrhea of unknown etiology, the adrenal glands as well as the pancreas should be examined by ultrasound and/or computerized tomography for the presence of a mass. Should an adrenal mass be discovered, it is necessary to evaluate the tumor for catecholamine production, despite the absence of clinical symptoms of a pheochromocytoma.