Vasoactive Intestinal Peptide-Secreting Tumor (VIPoma)

A VIPoma is a neuroendocrine neoplasm secreting vasoactive intestinal peptide (VIP), usually presenting with severe watery secretory diarrhea, which can result in hypokalemia and metabolic acidosis and with flushes. Hypochlorhydria, stimulation of glycogenolysis, and hypercalcemia can be also found in VIPoma patients. Plasma VIP levels are elevated in all patients with the VIPoma syndrome, which is also known as “watery diarrhea, hypokalemia, achlorhydria (WDHA)-syndrome”, or “Verner-Morrison syndrome”. The majority of VIPomas are located in the pancreas (75%) and (usually young) patients can present with VIP-producing neuroblastoma, ganglioneuroblastoma, ganglioneuroma, pheochromocytoma and paraganglioma, or neoplasms of the retroperitoneum and mediastinum. The first treatment aim of a VIPoma patient is to correct the fluid and electrolyte deficits. Administration of a somatostatin analog (SSA) can decrease flushing and diarrhea, further aiding in the restoration of fluid and electrolyte imbalances. Surgical resection should be considered in patients with a locoregionally confined VIPoma. In patients with a metastatic or unresectable VIPoma, SSAs likely prolong progression-free survival. Other treatment options include peptide receptor radionuclide therapy (PRRT) with radiolabeled SSAs, interferon alpha, everolimus, sunitinib, cytotoxic chemotherapy, or liver-directed therapies. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.