Rectosigmoid Endometriosis Mimicking Colorectal Cancer: A Case Report.

Rectosigmoid endometriosis is an uncommon cause of bowel obstruction and may closely mimic colorectal malignancy, particularly when imaging findings are nonspecific. We report the case of a 39-year-old woman who presented with acute bowel obstruction caused by a stenosing rectosigmoid lesion highly suspicious for cancer. Repeated endoscopic biopsies were inconclusive. Surgical management was performed and was complicated by hemorrhagic shock. Final histopathological examination revealed deep infiltrating endometriosis with rectosigmoid involvement. Postoperative imaging demonstrated extensive pelvic involvement of endometriosis, and subsequent attempts at bowel continuity restoration were unsuccessful due to dense adhesions. This case highlights the diagnostic challenges of bowel endometriosis mimicking colorectal cancer and underscores the importance of multidisciplinary evaluation and advanced imaging in women of reproductive age presenting with tumor-like colorectal lesions.