An unusual late presentation of imperforate hymen

The imperforate hymen is a rare gynecologic abnormality that may not be detected until the onset of menses, when hematocolpos causes symptoms due to an expanding pelvic mass.

A 19-year-old woman had primary amenorrhea, originally misdiagnosed as müllerian agenesis. Because of a combination of late onset of menses, vaginal dilation, and sexual intercourse, her hematocolpos remained relatively asymptomatic.

Proper diagnosis of the imperforate hymen could have been made earlier by contrasting the ultrasound findings with the absence of associated genitourinary and skeletal anomalies. Magnetic resonance imaging can detect a uterus not previously seen on ultrasound. An early imaging study may further prevent the misdiagnosis of congenital absence of the uterus.