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Zollinger-Ellison syndrome — ABIM Board MCQ

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HardGastroenterology/HepatologyZollinger-Ellison syndromeABIM Board

A 45-year-old has recurrent duodenal ulcers despite proton-pump inhibitor therapy and chronic watery diarrhea. Gastric pH is 1.5, fasting gastrin is markedly elevated and imaging shows a pancreatic neuroendocrine tumor. What mechanism is most likely?

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Correct answer: E — A gastrin-secreting tumor is driving excessive gastric-acid secretion

The best answer is “A gastrin-secreting tumor is driving excessive gastric-acid secretion”. A gastrinoma causes inappropriately high gastrin despite a strongly acidic stomach, leading to refractory peptic ulceration and acid-related diarrhea. Autoimmune achlorhydria can elevate gastrin but would not produce gastric pH 1.5, and the other mechanisms do not explain the ulcer-hypergastrinemia combination.

Reference: NIDDK Zollinger-Ellison Syndrome: https://www.niddk.nih.gov/health-information/digestive-diseases/zollinger-ellison-syndrome