In Zollinger-Ellison syndrome (ZES), a tumor (a gastrinoma) secretes the hormone gastrin, which stimulates the secretion of gastric acid. This leads to the development of ulcers in the stomach and duodenum (the first part of the small intestine).
In normal individuals, the stomach secretes the hormone gastrin after food enters the stomach. Gastrin is carried by the bloodstream to other parts of stomach. The main effect of gastrin is to stimulate the parietal cells of the stomach. Parietal cells are stomach cells that secrete gastric acid to aid in digestion. This acid plays a vital role in the digestion of food. This process is highly regulated so that the stomach produces gastrin in significant amounts only when necessary, as when there is food in the stomach.
The underlying entity of ZES is a tumor called a gastrinoma which secretes gastrin inappropriately. Marked overproduction of gastrin leads to hypersecretion of gastric acid by the parietal cells. The end result is severe ulcers of the stomach and duodenum that are more difficult to treat than common ulcers.
Gastrinomas are generally small tumors located in the pancreas or duodenum. They often occur in multiples in the same patient. More than half of all gastrinomas are malignant, with the potential to spread to nearby lymph nodes and also spread to the liver and other organs by way of metastasis. The malignant potential of gastrinoma is ultimately more life-threatening than the associated ulcers.
The ulcers in ZES are frequently located further down the gastrointestinal tract than common ulcers, and they may be multiple.
About 25% of patients with ZES also demonstrate other tumors of the endocrine system in a syndrome called Multiple Endocrine Neoplasia syndrome.
Kevin O. Hwang M.D., The Gale Group Inc., Gale, Detroit,