skip to main content

Zollinger-Ellison Syndrome — RACP Adult Medicine MCQ

Instant feedback + full explanation. One question, done properly.

HardGastroenterology & HepatologyZollinger-Ellison SyndromeRACP Adult Medicine

A 48-year-old woman presents with recurrent epigastric pain. Upper GI endoscopy reveals two duodenal ulcers despite PPI therapy. Serum gastrin is markedly elevated at 1200 pg/mL. What investigation should be performed next to localise the lesion?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Endoscopic ultrasound

Markedly elevated fasting gastrin with recurrent ulcers despite PPI therapy suggests Zollinger-Ellison syndrome (gastrinoma). EUS is the most sensitive modality for detecting pancreatic and duodenal gastrinomas. A secretin stimulation test confirms the diagnosis (paradoxical rise in gastrin >120 pg/mL). CT and somatostatin receptor scintigraphy are also used but EUS has superior sensitivity for small tumours.

Reference: eTG – 2025 – Gastrointestinal; NCCN – 2025 – Neuroendocrine Tumour Guidelines