What causes Zollinger-Ellison syndrome?
Zollinger-Ellison syndrome (ZES) is caused by a non–beta islet cell, gastrin-secreting tumor of the pancreas that stimulates the acid-secreting cells of the stomach 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 usually is located in the duodenum, the pancreas, and abdominal lymph nodes, but ectopic locations have also been described (eg, heart, ovary, gall bladder, liver, kidney).
Gastrin works on stomach parietal cells causing them to secrete more hydrogen ions into the stomach lumen. The increase in acidity contributes to the development of peptic ulcers in the stomach and duodenum. High acid levels lead to multiple ulcers in the stomach and small bowel.
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.
Gastrinomas may occur as single tumors or as multiple, small tumors. About one-half to two-thirds of single gastrinomas are malignant tumors that most commonly spread to the liver and lymph nodes near the pancreas and small bowel. Nearly 25 percent of patients with gastrinomas have multiple tumors as part of a condition called multiple endocrine neoplasia type I (MEN I). MEN I patients have tumors in their pituitary gland and parathyroid glands in addition to tumors of the pancreas. |
