FFinalistSouthampton · 2027
Endocrine
AKT · Endocrine/Paraneoplastic & neuroendocrinelow yield

Gastrinoma (Zollinger-Ellison)

Gastrin-secreting neuroendocrine tumour (pancreas/duodenum)

Overview

A gastrin-secreting neuroendocrine tumour (duodenum/pancreas) driving gastric acid hypersecretion — the Zollinger-Ellison syndrome. Causes multiple/refractory/atypically-sited peptic ulcers, diarrhoea and reflux. Diagnosed by a raised fasting gastrin (off PPIs) with high gastric acid; ~25% are part of MEN1. Treated with high-dose PPIs and tumour resection.

Recognise

  • Multiple, recurrent or atypically-located (e.g. distal duodenum/jejunum) peptic ulcers, refractory to standard treatment
  • Diarrhoea (acid inactivates pancreatic enzymes) and severe reflux; abdominal pain
  • Raised fasting GASTRIN with high gastric acid output; ~25% MEN1-associated

Red flags

  • Ulcer complications (bleeding/perforation); MEN1 association → screen
  • Gastrin falsely raised by PPIs — interpret carefully

Differentials & how to tell them apart

Helicobacter pylori / NSAID peptic ulcercommon cause — single, typical-site ulcer; normal gastrin
PPI-induced hypergastrinaemiaraised gastrin from acid suppression (not a tumour) — recheck off PPI
Antral G-cell hyperplasia / atrophic gastritisother causes of high gastrin — different acid output

Investigations

Fasting serum GASTRIN (markedly raised — measured OFF PPIs) with low gastric pH/high acid output; secretin stimulation test; localise (CT/MRI/EUS, somatostatin scan). Screen for MEN1 (calcium/PTH, prolactin).

Management

High-dose PPI + tumour localisation/resection

  1. 1Suspect with multiple/refractory/atypical ulcers + diarrhoea; confirm raised fasting gastrin (off PPIs) with high acid; localise. High-dose PPI controls symptoms; resect a localised tumour.Gate: Measure gastrin OFF PPIs (PPIs raise gastrin and mimic the result); ~25% are part of MEN1 → screen for hyperparathyroidism and pituitary tumours
  2. 2Surgical resection (curative if localised); somatostatin analogue for metastatic disease; MEN1 surveillance.
High-dose proton-pump inhibitor — controls acid hypersecretion/ulcers — the mainstay symptom control
Surgical resection — of localised tumour (potentially curative)
Somatostatin analogue — for metastatic/unresectable disease

Key points

Multiple/refractory/atypical peptic ulcers + diarrhoea + high gastrin (off PPI) = Zollinger-Ellison. High-dose PPI + resection. Always think MEN1.

Monitor & prognosis

Gastrin; ulcer healing; MEN1 screening.

Good if localised; variable if metastatic.

Source: ENETS/UKINETS