Duplication of the uterus with a noncommunicating functioning uterine horn

Incomplete duplication of the uterus with a functioning noncommunicating uterine horn is a rare developmental anomaly of the paramesonephric ducts. Although usually described in association with obstetric catastrophes, it has been reported recently in young women with gynecologic complaints. We describe a nulliparous patient with dysmenorrhea that had increased since menarche and a large pelvic mass. Surgical exploration revealed incomplete uterine duplication with a noncommunicating functioning uterine horn with a large hematosalpinx due to cryptomenorrhea. Inclusion of the anomaly in the differential diagnosis of young women with intractable, increasing dysmenorrhea and a pelvic mass will lead to prompt surgical intervention and obviate a catastrophic obstetric event.