Acute Gastrointestinal Bleed from a Gastrointestinal Stromal Tumour Impersonating an Arteriovenous Malformation of the Jejunum.

Gastrointestinal stromal tumours (GIST) are neoplasms which originate from the mesenchymal tissue of the gastrointestinal tract. We report on a GIST presenting with acute gastrointestinal bleeding that mimicked an arteriovenous malformation (AVM) on imaging and at surgery. A 61-year-old female presented with a short history of melaena and severe anaemia. After resuscitation, upper gastrointestinal endoscopy showed a profusely bleeding varix in the proximal jejunum which was treated with glue injection. Contrast-enhanced CT showed a heterogeneous lesion in the proximal jejunum with strong arterial phase enhancement, supplied by a branch of the superior mesenteric artery and drained by a prominent tributary of the superior mesenteric vein, suggestive of an AVM. The mass was resected, and histology revealed a GIST with no evidence of an AVM or angiodysplasia. A GIST may be considered, though imaging suggests a diagnosis of an AVM in patients presenting with acute gastrointestinal bleeds. In such circumstances, surgical resection and pathological assessment will be confirmatory.