Rectal endometriosis mimicking neoplasm

Abstract

In September 2011, a previous healthy 39-year-old woman visited our hospital complaining of a 5-month history of change in bowel movement with constipation and tenesmus. Fecal occult blood test (immune) was positive (>800 ng/mL). Barium enema showed an apple-core lesion over the upper rectum (Fig. 1). Because neoplasm of the rectum was believed to be present, the patient was admitted to our hospital for further management. Colonoscopy revealed segmental narrowing of the rectum with villous appearance of mucosa (Fig. 2). Although biopsies revealed unspecific inflammatory colitis, malignancy could not be ruled out. The findings on enhanced abdominal computed tomography (CT) were compatible with those of colonoscopy (Fig. 3). Thickening of the rectal wall with a narrowing of the lumen was observed. The patient underwent an exploratory laparotomy. During mobilization of the uterus, we found that the posterior wall of the uterus was firmly attached to the stenotic rectum. It was also difficult to dissect the rectovaginal septum because of severe scarring and inflammatory reactions. Low anterior resection was performed. An end-to-end anastomosis was created, with circular stapling using a double-stapled technique. There was no mucosal lesion, but segmental thickening of the upper rectal wall with stenosis of the lumen was present (Fig. 4). Pathologic examination of the specimen revealed endometriosis of the rectum (Fig. 5). The postoperative period has been eventful. Endometriosis with intestinal involvement is rare. Intestinal endometriosis may affect the ileum, appendix, sigmoid colon, and rectum and is more frequently located in the rectosigmoid (50e90%) [1,2]. There are two major theories to explain the pathogenesis of endometriosis. The most accepted theory is that of retrograde menstruation, which explains the presence