Endometriosis of the large bowel: a report of 11 cases.

The clinical and pathological features of 11 cases of large bowel endometriosis are reported, one of which also had lesions in the small intestine. All of the cases had rectal or rectosigmoid involvement. Altered bowel habit and pain were common symptoms but were rarely associated with the menstrual cycle. Sigmoidoscopy was generally unhelpful. Rectal or vaginal examination and barium enema often revealed a mass which was usually diagnosed preoperatively as a malignancy. A correct diagnosis was made preoperatively in only two cases; carcinoma was suspected in four and carcinoid in one case. Histological evidence of recent hemorrhage was confined to those cases where endometriosis seemed to be the major cause of intestinal symptoms. The colonic mucosa overlying the endometriotic deposits was commonly histologically abnormal. It showed a range of changes resembling colitis, solitary ulcer, prolapse or even neoplasm. An appreciation of these mucosal alterations is important to those reporting colonic and rectal biopsies; when observed to be focal in a female patient they should arouse a suspicion of endometriosis.