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The exact cause of Zollinger-Ellison syndrome remains unknown. But the sequence of events that occurs in Zollinger-Ellison syndrome is clear. The syndrome begins when a tumor (gastrinoma) or tumors form in your pancreas, duodenum or the lymph nodes adjacent to your pancreas.

Your pancreas sits behind and below your stomach. It produces enzymes that are essential to digesting food. The pancreas also produces several hormones, including gastrin, a hormone that controls stomach acid production. Digestive juices from the pancreas, liver and gallbladder mix in the duodenum, the part of the small intestine next to your stomach. This is where digestion reaches its peak.

The tumors that occur with Zollinger-Ellison syndrome are made up of cells that secrete large amounts of gastrin, which in turn causes the stomach to produce far too much acid. The excessive acid then leads to peptic ulcers and sometimes to diarrhea.

Besides causing excess acid production, the tumors may be cancerous (malignant). The tumors themselves grow slowly, but the cancer can spread elsewhere — most commonly to nearby lymph nodes or your liver.

Association with MEN I

Zollinger-Ellison syndrome may be caused by an inherited condition called multiple endocrine neoplasia, type I (MEN I). People with MEN I have multiple tumors in the endocrine system in addition to pancreatic tumors. They also have tumors in the parathyroid glands and may have tumors in their pituitary glands. About 25 percent of people who have gastrinomas have them as part of MEN I.

Oct. 11, 2012

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