Partial hydatidiform mole and coexisting viable twin pregnancy.

Herlyn-Werner-Wunderlich (HWW) syndrome is a rare müllerian duct anomaly with uterus didelphys, unilateral obstructed hemivagina, and ipsilateral renal agenesis. Patients with this syndrome generally present after menarche with pelvic pain and mass and, rarely, primary infertility in later years. Strong suspicion and knowledge of this syndrome are mandatory for an accurate diagnosis. A 14-year-old female patient presented with acute retention of urine and abdominopelvic pain. Her condition was diagnosed with the use ultrasonography and magnetic resonance imaging as a case of HWW syndrome. She was treated with vaginal hemiseptal resection. The HWW syndrome should be considered among the differential diagnoses in girls with renal anomalies presenting with pelvic mass, symptoms of acute abdominal pain, and acute urinary retention.