Uterus-like mass in the left broad ligament misdiagnosed as a malformation of the uterus: A case report of a rare condition and review of the literature

Abstract

To describe a rare extrauterine mass of an unknown origin that was composed of smooth muscle with a central cavity lined by endometrium, which resembled a uterus. Case report. Academic teaching hospital. A 17-year-old girl with severe dysmenorrhea was found to have a uterus-like mass composed of smooth muscle and lined by endometrium in the left broad ligament. Abdominal surgery. The mass was successfully removed surgically, and her dysmenorrhea resolved. Histopathological examination revealed that the uterus-like mass was composed of smooth muscle with a cavity lined by endometrial glands and stroma. The histogenesis of a uterus-like mass is theorized to be a Müllerian system anomaly, metaplastic change, and/or heterotopia. We believe metaplasia is the most likely cause in this case. Alhough rare, it should be considered in the differential diagnosis of dysmenorrhea of uncertain etiology.