ABSTRACT
Herlyn-Werner-Wunderlich syndrome represents a complex female genital malformation with uterus didelphys, unilateral low vaginal obstruction, and ipsilateral renal agenesis, all 3 being secondary to mesonephric duct-induced müllerian anomalies. Clinically, this usually presents in postpubertal adolescent or adult women where hematometrocolpos produces a more pronounced mass effect and pain on the side of the obstructed hemivagina. It is extremely rare for this to present in infancy and early childhood because imaging may not show the small prepubertal uteri and vaginas clearly. We describe a 4-year-old girl with all of the features of this syndrome. Ipsilateral renal agenesis with a pelvic mass should raise the level of suspicion for this syndrome. Magnetic resonance imaging will confirm the diagnosis, so that early endoscopic resection of the obstructing vaginal septum can be carried out as definitive treatment. Long-term outcome is quite good with expectation of normal fertility.
