Urinary hydrocolpos, cloacal malformation and pre-axial polydactyly: a rare variant of neonatal hydrocolpos.

Hydrocolpos is characterized by a vaginal obstruction with cystic dilatation of the vagina. The latter is usually caused by accumulation of cervical and endometrial mucus but in rare instances urine is accumulated through a vesicovaginal fistula proximal to the obstruction. Hydrocolpos and hydrometrocolpos may be associated with other malformations, such as postaxial polydactyly, anal atresia, esophageal atresia, renal agenesis, genital anomalies, and cardiopathy. Each neonate presenting with hydrocolpos should be evaluated for other clinically silent malformations, such as hamartoblastoma of the hypothalamic region. We report a patient with urinary hydrocolpos and cloacal malformation; it is the first case of hydrocolpos with pre-axial polydactyly. We briefly describe embryogenesis of the different types of vaginal obstruction and discuss prenatal and neonatal diagnosis and differential diagnosis.