Colonic Endometrioma: A Classic Presentation with Cyclical Bleeding

Purpose: A 28 year old female experienced episodic copious rectal bleeding of six months duration. The bleeding had a cyclical nature with heavy bleeding around the time of menstruation. Abdominal and pelvic CT scan with contrast demonstrated a 2.3 × 2.2 × 3 cm intraluminal mass located in the anterior wall of the rectosigmoid junction (Figure 1). Colonoscopy showed a firm, well-circumscribed submucosal mass protruding into the colonic lumen at the rectosigmoid junction about 15 cm from the anal verge (Figure 2). The mass was causing colonic obstruction and prevented passage of a slim scope beyond this point. Biopsy showed normal colonic mucosa with hyperplastic changes. Surgical resection revealed a firm partially obstructing rectosigmoid mass. Histology of the surgical specimen revealed normal colonic architecture with endometrial glands and stroma (Figure 3). Five adjacent lymph nodes were free of pathology. Colonic involvement from pelvic endometriosis is an unusual but well described condition in menstruating women. Bowel obstruction from endometriosis is rare. The majority of patients are asymptomatic but can present with abdominal pain, diarrhea, rectal bleeding and anemia. Submucosal colonic tumors include leiomyomas, GIST, lipomas, carcinoids and endometriomas. Surgical resection is curative in most patients.Figure 1Figure 2Figure 3