An internal iliac artery aneurysm causing a colonic obstruction: report of a case.

An 80-year-old male patient presented with the chief complaints of a sudden onset of pain in the right lower quadrant and constipation of 3 days' duration. In computerized tomographic examination an aneurysm of right internal iliac artery and an abnormally enlarged descending colon were seen. During an emergency operation a small rupture in the subserosa of the rectosigmoid junction was found.