Definition

A very rare tumor that usually forms in the islet cells of the pancreas and makes the hormone vasoactive intestinal peptide (VIP). VIP helps control the secretion of water, salts, enzymes, and gastric acid during digestion and relaxes certain muscles in the digestive tract. Signs and symptoms of VIP-secreting tumor include chronic watery diarrhea, dehydration, abdominal pain, nausea, flushing or redness in the face, weight loss, and very low levels of potassium in the blood. Most VIP-secreting tumors are cancer and have often spread to other parts of the body when they are found. VIP-secreting tumor is a type of pancreatic neuroendocrine tumor. Also called VIP-producing neuroendocrine tumor and VIPoma.