Angiodysplasia of the right colon: a cause of gastrointestinal bleeding.

Thirty-four patients with intermittent lower gastrointestinal bleeding were diagnosed angiographically as having angiodysplasia of the cecum and right colon. Repeated barium and endoscopic examinations were negative. Right colectomy was performed on 17 patients, who were followed postoperatively for up to 7 years. Of these, four patients rebled, two of whom had angiographic evidence of related lesions involving other parts of the colon and terminal ileum. Silicone rubber injection and tissue-clearing techniques on the specimens have facilitated the pathologic identification of these lesions. Histologically, they are dilated submucosal veins and arteries associated with areas of overlying mucosal thinning and occasional ulcerations. Although the pathogenesis of the lesion is unknown, we think they are acquired rather than congenital and result from chronic submucosal arteriovenous shunting secondary to mucosal ischemia. Of the 34 patients, 17 had a history of cardiac disease.