Zollinger-Ellison Syndrome (ZES)

Clinical

ZES is an inflammatory condition caused by gastrin-secreting tumors (gastrinomas). Gastrinomas are usually located in duodenum, pancreas, or the adjacent lymph nodes, a region dubbed the “gastrinoma triangle.” Hypersecretion of gastrin leads to excess acid production and multiple GI ulcerations. Thus, the disease is hallmarked by multiple ulcers or ulcers in atypical locations (i.e. jejunum). ZES may occur sporadically (75%) or as a part of MEN1 (hyperparathyroidism, pancreatic endocrine tumors, and pituitary tumors). Epidemiologically, 0.1-1% of all patients with duodenal ulcers have ZES.

Clinically, patients present with abdominal pain, diarrhea, GERD, GI bleeding, weight loss, nausea, and vomiting. Diagnostic tests include fasting serum gastrin levels, gastric acid secretory tests, and secretin stimulation tests.

Treatment consists of control of gastrin hypersecretion, using drugs such as proton-pump inhibitors and octreotide. Surgical resection is the definitive treatment.

Radiology

Somatostatin receptor scintigraphy (SRS) is the most sensitive imaging modality for detection of primary or metastatic lesions in ZES and, thus, is the imaging modality of choice in ZES.

CT aids in localizing the primary tumor and evaluating for metastatic disease. However, its sensitivity for primary tumor localization is only 50%, and frequently, tumors smaller than 1 cm are missed.

Fluoroscopy typically shows ulcerations, as well as fold thickening and luminal narrowing from edema.

Other imaging studies, such as magnetic resonance imaging and abdominal ultrasound, also can be performed.  However, sensitivity is lower compared to CT scan or SRS.