Idiopathic colonic varices: an unusual cause of massive lower gastrointestinal hemorrhage.

We report a patient with massive lower gastrointestinal bleeding, probably from extensive colonic varices. Despite lengthy investigation, the etiology of the colonic varices was not determined. There are numerous reports in the literature of bleeding from colonic varices attributed to portal hypertension from cirrhosis or venous obstruction. However, bleeding from colonic varices located in the entire colon without demonstrable cause have only rarely been reported.