Robert L. Lebowitz, M.D. Children' s Hospital, Harvard Medical School Boston, Massachusetts

This four-month-old girl presented with febrile urinary tract infection. This was treated and she was put on prophylactic antibiotic. She came for routine follow-up ultrasound and VCUG. Ultrasound showed bilateral htdroureteronephrosis (fig 1&2) and a large pelviabdominal mass filled with debris (fig 3) that was originally thought to represent the urinary bladder. VCUG showed right reflux with the ureter draped around the mass (fig 4). Repeat ultrasound showed the mass was a large debris-filled vagina (fig 5), behind the almost empty bladder (arrow). At surgery, she was found to have a distal vaginal membrane that was excised, releasing a large volume of secretions

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