Intestinal obstruction due to rectal endometriosis.

We report a case of a premenopausal woman with severe constipation causing intermittent obstruction. Colonoscopy revealed a tight rectal stricture; however, mucosal biopsies were normal. Exploratory surgery revealed an intense fibrotic reaction involving the rectum and uterus, necessitating a simultaneous low anterior resection and hysterectomy. Pathology established a diagnosis of endometriosis. Preoperative diagnosis of rectal endometriosis can be difficult to establish. Endometrial deposits do not invade the mucosa; therefore, colonoscopy with biopsies are frequently non-diagnostic. Surgery may be the only definitive way to obtain a certain diagnosis. In cases involving rectal strictures of unknown etiology in premenopausal women, rectal endometriosis must be included in the differential diagnosis.