Superior mesenteric vein stenosis complicating Crohn's disease.

BACKGROUND Superior mesenteric vein stenosis as a consequence of mesenteric fibrosis, causing the development of small bowel varices, is an unrecognised association of Crohn's disease. CASE REPORTS Two cases of gastrointestinal bleeding occurring in patients with Crohn's disease, and a third case, presenting with pain and diarrhoea, are described. In all three patients, visceral angiography showed superior mesenteric vein stenosis with dilatation of draining collateral veins in the small bowel. Overt gastrointestinal bleeding or iron deficiency anaemia resulting from mucosal ulceration is common in Crohn's disease, but acute or chronic bleeding from small bowel varices as a result of superior mesenteric vein stenosis due to fibrosis has not previously been reported.