Diffuse hemangiomatosis of the colon.

We report extensive colonic hemangiomatosis in two young adults. In the first, the hemangioma contiguously involved the entire colon. In the second, a large venous angioma affected the bladder, rectosigmoid, and descending colon. Venous angioma, a variant of hemangioma, is frequently confused with cavernous hemangioma because of their similar histologic appearance. The angiographic features, however, may enable a more accurate preoperative diagnosis and prevent unwarranted biopsy. We review and put into perspective pertinent previous reports of cavernous and venous angioma.