Lower abdominal mass in a 16-year old adolescent: an unusual presentation of posterior urethral valves.

Posterior urethral valves (PUV) are now commonly suspected on antenatal ultrasound, but can present with a broad spectrum of severity postnatally. Rarely, the diagnosis is missed until adolescence or adulthood when the patient usually presents with lower urinary tract symptoms. We describe an even rarer case of PUV in an adolescent who first presented with renal failure and a palpable lower abdominal mass due to urinary retention.