[Rectal mass revealing peritoneal inclusion cyst with peritoneal endometriosis incidentally discovered: About a case and review of the literature].

Peritoneal inclusion cyst is a rare benign tumor. It usually affects women of reproductive age. Its etiology is poorly understood; a history of endometriosis, pelvic inflammatory disease and pelvic surgery are sometimes implicated in its occurrence. Its diagnosis is difficult with complex management. We report the case of a 29-year-old woman presenting a rectal mass for which the analysis of echo-endoscopic samples was not contributory. The PET-scan revealed a rectal submucosal mass and deep adenopathy. An exploratory laparoscopy was performed, and allowed to remove cystic inflammatory areas and lymph nodes. The histopathological study confirmed the diagnosis of peritoneal inclusion cyst with endometriosis and reactive adenitis. Peritoneal inclusion cyst is a rare condition that develops at the expense of the serosa. The risk of recurrence is high with a possibility of malignant transformation. Excision and monitoring are essential for good management.