Fetal hydrometrocolpos and congenital imperforate hymen: Prenatal and postnatal imaging features

Congenital imperforate hymen is probably the most common obstructive anomaly of the female reproductive tract. The accumulation of fluid in the genital tract leads to a distended uterus and vagina, causing hydrometrocolpos. Prenatal diagnosis of fetal hydrometrocolpos is uncommon, with only 22 cases reported in the literature and only a few cases of prenatal imaging of this condition available to date. The main ultrasound finding is a fetal pelvic mass posterior to the bladder and anterior to the rectum. We present the case of a 37-week female fetus with a fetal pelvic mass detected in a routine obstetric ultrasound examination, and the correlation between the prenatal and postnatal findings.