Transmural Rectosigmoid Endometriosis Causing Rectal Bleeding and Partial Colonic Obstruction

Abstract

Introduction: Intestinal endometriosis occurs in 10% of endometriosis cases. Most patients are asymptomatic while some may experience non-specific gastrointestinal symptoms. Diagnosis is challenging due to lack of characteristic clinical, radiological, and endoscopic findings. Endoscopic biopsies are rarely helpful as intestinal endometriosis frequently involves deeper layers of the bowel wall. We report a rare occurrence of transmural rectosigmoid endometriosis and its unusual presentation as rectal bleeding and partial colonic obstruction. Case Presentation: A 46 year-old-woman presented with six months of severe constipation and hematochezia that worsened monthly, around the time of menstruation. Colonoscopy revealed a circumferential and partially obstructing rectosigmoid lesion which was biopsied, but pathology was non-diagnostic. CT abdomen and pelvis revealed a 3-cm intraluminal mass in the mid-sigmoid colon and a 4-cm well-circumscribed mass in the right adnexa. A pelvic ultrasound confirmed a complex right ovarian cyst, as well as a left hemorrhagic ovarian follicular cyst. Labs revealed normal CBC, CMP, CEA and CA-125 levels. The patient was referred to colorectal and gynecologic oncology surgery, and subsequently underwent robotic-assisted low anterior resection of the rectosigmoid colon with anastomosis, and total laparoscopic hysterectomy with bilateral salpingo-oophorectomy. Surgical pathology of the rectosigmoid colon ultimately revealed endometriosis involving the entire thickness of the bowel wall with focal extension into the mucosa. On follow up visits, the patient reported complete resolution of rectal bleeding and constipation. Discussion: Intestinal endometriosis rarely affect the entire thickness of the bowel wall, making endoscopic biopsies typically futile. In cases where mucosal endometriosis was confirmed with endoscopic biopsies, patients were post-menarche women with cyclic gastrointestinal symptoms and hematochezia, similar to our patient. Despite initial non-diagnostic endoscopic biopsies, our patient did prove to have mucosal involvement of the colon on surgical pathology. Symptomatology of cyclic rectal bleeding and severe constipation in post-menarche women may be an indication of transmural involvement of intestinal endometriosis and should be considered in the differential diagnosis. Moreover, these patients may benefit from more thorough endoscopic sampling which may improve the diagnostic yield of endoscopy.Figure 1Figure 2