A 50-year-old man presents with recurrent peptic ulcers despite eradication of H. pylori (confirmed negative on UBT). Fasting serum gastrin is 850 pg/mL (normal <100). Secretin stimulation test shows a paradoxical rise in serum gastrin to 1400 pg/mL (increase >120 pg/mL). CT scan shows a 1.5 cm mass in the duodenal wall. The diagnosis is:

• A G-cell hyperplasia
• B Gastrinoma (Zollinger-Ellison syndrome) ✓
• C Pernicious anemia with antral G-cell hyperplasia
• D Short bowel syndrome

Explanation

Zollinger-Ellison syndrome (ZES) is characterized by fasting hypergastrinemia (>1000 pg/mL is virtually diagnostic; levels >100 are suspicious) with a secretin stimulation test showing a paradoxical rise in gastrin by >120 pg/mL — the diagnostic standard. Gastrinomas are found in the 'gastrinoma triangle' (duodenum most common site in sporadic ZES). G-cell hyperplasia shows hypergastrinemia but gastrin does not rise paradoxically with secretin; it may decrease. ZES requires proton pump inhibitors and surgical resection if localized.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.