Zollinger-Ellison Syndrome (ZES) is a rare disorder characterized by the formation of one or more tumors known as gastrinomas in the pancreas or duodenum. These tumors secrete excessive levels of the hormone gastrin, which stimulates the stomach to produce too much acid. This leads to recurrent peptic ulcers, gastroesophageal reflux disease (GERD), and other gastrointestinal issues.
