Zollinger–Ellison Syndrome (ZES) is caused by a non–beta islet cell (islet of Langerhans), gastrin-secreting tumor of the pancreas that stimulates the acid-secreting cells of the stomach (parietal cells) to maximal activity, with consequent gastrointestinal mucosal ulceration. ZES may occur sporadically or as part of an autosomal dominant familial syndrome called multiple endocrine neoplasia type 1 (MEN 1). The primary tumor is usually located in the pancreas, duodenum or abdominal lymph nodes, but ectopic locations have also been described (e.g., heart, ovary, gallbladder, liver, kidney).

Signs and symptoms

Patients with Zollinger–Ellison syndrome may experience abdominal pain and diarrhea. The diagnosis is also suspected in patients without symptoms who have severe ulceration of the stomach and small bowel, especially if they fail to respond to treatment.