Multiple endocrine neoplasia type I syndrome (MEN I) results in parathyroid, anterior pituitary, and pancreatic islet tumors. An uncommon tumor in MEN I is the vasoactive intestinal polypeptide-producing tumor (VIPoma), which usually presents with diarrhea and hypokalemia. We describe a case of MEN I and VIPoma presenting with hypercalcemia and hypokalemia but no diarrhea. This 19-year-old woman with a family history of MEN I presented with metabolic acidosis, hypokalemia, hypercalcemia, and intact parathyroid hormone (iPTH) of 11 pg/mL (normal, 8 -48 pg/mL). A computed tomography scan revealed a pancreatic mass. VIP concentration was 249 pg/mL (normal, Ͻ50). The pancreatic mass was resected, stained positive for VIP, and her VIP level normalized. VIPomas usually present with diarrhea, resulting in metabolic acidosis and hypokalemia. This patient demonstrated hypokalemia and hypercalcemia without diarrhea or elevated parathormone. Thus, VIPomas can have biologic actions, such as hypokalemia and hypercalcemia without inducing diarrhea and should be considered in the differential diagnosis of hypercalcemia in MEN I. Key Words: vasoactive intestinal polypeptide, diarrhea, multiple endocrine neoplasia (The Endocrinologist 2005;15: 320 -324) Learning Objectives • Outline the place of vasoactive intestinal polypeptide (VIP)-producing tumors, or VIPomas, in the context of all islet-cell tumors of the pancreas and as a component of multiple endocrine neoplasia type I (MEN I) syndrome. • Describe the ways in which this patient's clinical and biochemical findings were in accord with or differed from those usually found in patients having a VIPoma. • Give examples of how VIP produces the clinical and biological abnormalities found in patients having a VIPoma as part of the MEN I syndrome.M ultiple endocrine neoplasia type I syndrome (MEN I) is a genetic condition in which affected family members can present with tumors of neuroendocrine tissue, including parathyroid glands, the anterior pituitary, and pancreatic islet cells. 1 The islet cell tumors tend to be the most aggressive and often decrease longevity. The most common islet cell tumors in MEN I are gastrinomas and insulinomas, with vasoactive intestinal polypeptide-producing tumors (VIPomas) occurring infrequently. 2 VIPomas usually present with secretory diarrhea, hypochlorhydria, and hypokalemia. 3 We describe a patient with MEN I syndrome and VIPoma with an unusual presentation of hypokalemia and hypercalcemia without diarrhea.
CASE REPORTA 19-year-old previously healthy woman presented to her local emergency room with a 1-week history of diffuse abdominal pain, lethargy, nausea, one episode of vomiting, and a decreased appetite. She experienced a 10-pound weight loss during the previous week and had eaten only one meal during that time. She attributed her symptoms to a "nervous stomach" caused by stress from school and interpersonal relationships. She denied loose or watery stools. She was on no medications and denied previous tobacco, alcohol, and drug use or rec...
