Rectosigmoid endometriosis: endoscopic ultrasound features and clinical implications

The main area of the gastrointestinal tract affected by deep pelvic endometriosis is the rectosigmoid colon in 3-37% of cases. Due to the risk of infiltration and the clinical symptoms of endometriosis, with pain and infertility, the condition may require surgical resection. Preoperative imaging diagnosis of rectosigmoid involvement is therefore important. Rectal endoscopic ultrasonography (EUS), which is already used for the staging of anorectal carcinoma and submucosal lesions, may be a promising technique for this indication. The present study was conducted in order to describe the endosonographic appearance of rectosigmoid endometriosis, and to define the potential relevance of the technique to the choice of resection method.

Between 1993 and 1997, 46 women (mean age 31) with deep pelvic endometriosis underwent imaging investigations and surgical resection. The clinical and imaging findings, and the surgical and histological features identified--mainly with regard to infiltration of the rectal wall--were compared retrospectively. The impact of the EUS findings on the decision on whether or not to carry out resection, either by laparoscopy or open abdominal surgery, was also examined.

When there was deep pelvic endometriosis with suspected rectal wall infiltration, EUS showed normal anatomy in nine patients, endometriotic lesions without rectal wall infiltration in 12, and typical rectal infiltration in 25. The lesions were confirmed by the surgical findings during therapeutic laparoscopy (n = 22) and laparotomy (n = 25), as well as by clinical follow-up. Rectal wall infiltration, demonstrated in all cases using EUS, had initially been suspected on the basis of clinical examinations, rectoscopy, barium enema, computed tomography, and magnetic resonance imaging in 62%, 50%, 33%, 67% and 66% of cases, respectively.

EUS is a simple and noninvasive technique capable of correctly diagnosing rectal wall infiltration in deep pelvic endometriosis. It may be helpful in determining the choice between laparoscopy and laparotomy when complete resection is indicated.