Zollinger-Ellison Syndrome
Zollinger-Ellison syndrome (ZES) is a rare disorder that causes tumors in the pancreas and duodenum ulcers in the stomach and duodenum. The pancreas is a gland located behind the stomach. It produces enzymes that break down fat, protein, and carbohydrates from food, and hormones like insulin that break down sugar. The duodenum is the first part of the small intestine.
The tumors secrete a hormone called gastrin that causes the stomach to produce too much acid, which in turn causes stomach and duodenal ulcers (peptic ulcers). The ulcers caused by ZES are less responsive to treatment than ordinary peptic ulcers. What causes people with ZES to develop tumors is unknown, but approximately 25 percent of ZES cases are associated with a genetic disorder called multiple endocrine neoplasia type 1, which is associated with additional disorders.