Colonoscopic Diagnosis of Polypoid Endometriosis in the Sigmoid Colon

Purpose: Gastrointestinal (GI) tract is the most common site for extra pelvic endometriosis. Endometriotic deposits are rarely mucosal and even if present, endoscopic biopsies are usually non-diagnostic due to secondary mucosal changes. Methods: 30-year-old female with c-section 9 years ago complained of abdominal cramps, bloating, constipation and rectal bleeding during menstruation for 3 years with recently increasing severity. She was diagnozed with pelvic endometriosis and had partial relief despite multiple medical treatments. Her physical exam is unremarkable except for moderate tenderness to palpation in left lower quadrant. Results: She had normocytic anemia with hemoglobin of 9.8 gm/dl and all other labs were unremarkable. CT of the abdomen revealed thickening of the sigmoid colon and mildly distended proximal colon. Colonoscopy immediately after menstruation revealed an almost completely obstructing polypoid sigmoid mass and adherent blood clots. Mucosal biopsies revealed endometrial glands which confirmed the diagnosis. Sigmoid resection, total abdominal hysterectomy and bilateral salpingo-oopherectomy were subsequently performed. Conclusion: Endometriosis occurs in about 10% of all women and colorectal endometriosis (CRE) accounts for 5-12% of all cases. Rectum and sigmoid colon are the most common GI sites with a combined estimate of 70-90%. Although numerous case reports of CRE exists, mucosal involvement is rare and endoscopic diagnosis usually has low yield even in cases with visible lesions. Mucosal changes can mimic IBD or even neoplasm. Our case adds to the growing body of polypoid endometriosis which was confirmed on endoscopic biopsies. Future studies are needed to elucidate if the diagnostic yield is increased by biopsying in the immediate post menstrual period as in our case, when the endometrial glands are more superficial.Figure: Colonoscopic view.Figure: Endometrial glands.