Müllerian Endometrioid Adenocarcinoma Arising from Colonic Endometriosis: Report of a case that presented with bowel obstruction

Gastrointestinal endometriosis-associated malignancies are rare and diagnostically challenging. Mullerian endometrioid adenocarcinoma is the most common and likely to be confused with a primary colonic adenocarcinoma due to their overlapping histological features. We present a case of mullerian endometrioid adenocarcinoma arising from colonic endometriosis in a 61year-old woman who presented with bowel obstruction. The tumor had histological features remarkably simulating a primary colonic adenocarcinoma because of its transmural involvement of the sigmoid colon, colonization of the colonic surface epithelium and mesenteric lymph node metastasis. A high index of suspicion in conjunction with careful histological and immunohistochemical examination (CK7, CK20, CDX2, CD10, ER and PR immunostains) is important for establishing a correct diagnosis.