islet cell tumor

islet cell tumor A tumor that arises from the islet cells of the pancreas. The islet cells normally produce insulin and other hormones, and so the tumors frequently, but not always, produce one of these hormones. Islet cell tumors can be benign or malignant and generally cause symptoms related to the hormone produced by the tumor. Specific types of islet cell tumors include insulinomas, glucagonomas, and gastrinomas. People with a family history of multiple endocrine neoplasia type I (MEN I) are at an increased risk for the development of islet cell tumors. Treatments depend upon the type of tumor and may include surgery, chemotherapy, and medications to treat the symptoms of hormone excess.