1. RECTAL ENDOMETRIOSIS MIMICKING A RECTAL CANCER. A CASE REPORT
RECTAL ENDOMETRIOSIS MIMICKING A RECTAL CANCER. A CASE REPORT. Mohamed Zied Ben Abdessalem, Fatma medhioub, Mohamed Salah Jarrar, Amine Gouader, Mohamed Hedi Mraidha, Amine Elghali, Rafik ghrissi, Fehmi Hamila, Rached Letaief Department of General and Digestive Surgery - Farhat Hached University Hospital of Sousse - TUNISIE

2. INTRODUCTION
Endometriosis is an ectopic implantation of the uterine endometrial tissue. Most victims are in their reproductive age and often with associated pelvic pain and infertility. Gastrointestinal involvement is known to occur in 3 to 37% of cases, recto-sigmoid being the most common site of involvement. Symptoms include alteration in bowel habits, dyschezia and rectal bleeding. Complications including bowel obstruction, stricture and perforation may occur. volvulus and intussusception secondary to bowel involvement have also been described in the literature. The lack of pathognomonic signs makes the diagnosis difficult mostly because the main differential diagnosis is with neoplasm.

3. CASE REPORT
We report the case of a 32 year-old woman with no particular history, 0 gesta 0 para. She complained of abdominal pain and inability to have a bowel movement or pass gas. To be noted that these symptoms did not appear during menstruation. She had regular menses, no history of transit neither disorder nor weight loss. Examination and abdominal X-ray confirmed the bowel obstruction. A CT-scan of the abdomen and the pelvis showed a rectal tumor and bilateral ovarian cysts. A decision was made to perform surgery and the patient had a loop colostomy via an elective approach. Rectoscopy was performed three times and showed an impassable obstructing mass at 8 cm above the anal verge. The pathologic report revealed fragments of mucosa consistent with rectal endometriosis. The abdomino-pelvic MRI showed a mass extending from the posterior wall of the vagina to the middle rectum causing wall thickening and stenosis of the lumen and the bilateral ovarian cysts. The patient had received the GnRH agonist for 6 months. The evolution was characterized by the disappearing of the ovarian cysts and the persistence of the rectal tumor. The surgical exploration showed a middle rectum mass that had infiltrated the posterior uterine wall. We performed an anterior resection of the rectum with an end to end colorectal anastomosis and a covering loop ileostomy. The histopathological study of the specimen confirmed that it was endometriosis involving the full thickness of the bowel wall with no evidence of malignancy.

4. CONCLUSION
Our case mimicked at first a rectal cancer because of similar radiological and endoscopic findings. Only deep and multiple biopsies allowed us to recall the diagnosis of rectal endometriosis. In our report, we try to impress the fact that this differential should always be considered especially in women of reproductive age presenting with colorectal neoplasm-like symptoms.