Deep Infiltrating Endometriosis of the Sigmoid Colon Masquerading as Colon Cancer

Superficial endometriosis involving the serosa of the colon is not an uncommon presentation. However, Deep Infiltrating Endometriosis (DIE) involving more than 5mm of the peritoneal surface reaching up to the muscularis propria and submucosa is rare. Further DIE causing luminal stricture and colonic obstruction occurs in less than 1.7% of the cases. We report a case of a forty six year old woman who initially presented for evaluation of cyclical abdominal pain. Radiologic and endoscopic investigations were suggestive of a malignancy. She underwent surgery including laparoscopic low anterior resection of sigmoid colon with side-to-end coloproctostomy and bilateral salpingo-oopherectomy. The histopathology revealed multiple endometriotic implants involving the submucosa, muscularis propria and serosa of the sigmoid colon. A left ovarian endometrioma was also identified. Our case highlights the diagnostic challenge in establishing an accurate pre-operative diagnosis and differentiates DIE from colon cancer. A multidisciplinary team approach with a combination of medical and surgical interventions can achieve effective therapy.