A GASTRIN-secreting neuroendocrine tumor of the non-beta ISLET CELLS, the GASTRIN-SECRETING CELLS. This type of tumor is primarily located in the PANCREAS or the DUODENUM. Majority of gastrinomas are malignant. They metastasize to the LIVER; LYMPH NODES; and BONE but rarely elsewhere. The presence of gastrinoma is one of three requirements to be met for identification of ZOLLINGER-ELLISON SYNDROME, which sometimes occurs in families with MULTIPLE ENDOCRINE NEOPLASIA TYPE 1; (MEN 1).

A tumor that causes overproduction of gastric acid. It usually begins in the duodenum (first part of the small intestine that connects to the stomach) or the islet cells of the pancreas. Rarely, it may also begin in other organs, including the stomach, liver, jejunum (the middle part of the small intestine), biliary tract (organs and ducts that make and store bile), mesentery, or heart. It is a type of neuroendocrine tumor, and it may metastasize (spread) to the liver and the lymph nodes.

(gastrin-producing neuroendocrine tumor) A gastrin-producing neuroendocrine tumor. It is usually located in the pancreas but it is also found at other anatomic sites, including the stomach and small intestine.

A gastrinoma is a gastrin-producing tumor usually located in the pancreas or the duodenal wall. Gastric acid hypersecretion and aggressive, refractory peptic ulceration result (Zollinger-Ellison syndrome). Diagnosis is by measuring serum gastrin levels. Treatment is proton pump inhibitors and surgical removal.

A gastrinoma is a gastrin-secreting tumor that can occur in the pancreas, although it is most commonly found in the duodenum. Duodenal wall gastrinomas have been identified in 40-50% of patients.