[Dysmenorrhea and pelvic pain secondary to an accessory and cavitated uterine mass].

An accessory and cavitated uterine mass (ACUM) is a rare anomaly with an embryological origin of dysfunctionning female gubernaculum. It is an accessory mass internally lined with normal endometrium, separated from the uterine cavity and located near the insertion of the round ligament. ACUM's clinical manifestations are severe dysmenorrhea and/or chronic pelvic pain. It is a relatively unknown condition, which makes its diagnosis complicated and suggests a large differential diagnosis. We report the case of a 31-year-old female presenting with pelvic chronic pain and crippling dysmenorrhea. The initial work-up consists of a magnetic resonance imaging showing an interstitial lesion possibly corresponding to an ACUM. This supposition was then confirmed by histopathology.