[Urinary hydrometrocolpos by persistent urogenital sinus; prenatal diagnosis and neonatal management].

Urogenital Sinus (UGS) malformation can be ascribed to an arrest of normal embryonic vaginal development. Neonates with UGS frequently have ambiguous genitalia, rarely the vulva may be normal. The aim of this work is to define the role of prenatal sonography in the diagnosis of UGS associated with hydrocolpos and/or hydrometrocolpos. The Authors report their experience on 3 cases of UGS without ambiguous genitalia with hydrometrocolpos, in which prenatal sonography had shown a cystic dilatation in the pelvis. After birth the 3 neonates presented with female genitalia and a single orifice between the labia. The pelvis sonography showed in all the cases an hydrometrocolpos with a large vagina and a compressed and anteriorly located bladder. Voiding cystourethrogram, genitography and genitoscopy confirmed the presence of an UGS with urinary retention inside the vagina and stenosis of the distal portion of the vagina itself. An early drainage of the capacious vagina was performed in the three patients. There are very few reports in the literature of UGS with hydrometrocolpos diagnosed in utero. The cystic dilatation of the vagina is always misdiagnosed with a distended bladder. In utero, infact, the bladder can not be identified being displaced anteriorly by the vagina. The presence of a fluid-debris level inside the cystic anechoic mass must be considered a crucial finding. Multiple echoes are due to vaginal secretions. Prenatal ultrasound has then a definitive role in detecting an obstructed genital tract. This allows to rapidly drain the vagina relieving urinary tract obstruction.