Unusual case of bladder duplication: complete duplication in coronal plane with single urethra and no associated anomalies.

Duplication of the bladder is an unusual congenital anomaly. Complete and incomplete forms are well defined in published reports. We present an unusual case of a 3-year-old boy with two separate-walled bladders, one lying in front of the other, communicating through a tiny septum, at the neck of the primary bladder that drained to a normal single urethra. This type of isolated bladder anomaly was not defined in the classification of the duplication of the bladder. In patients with a lower abdominal cystic mass, complete bladder duplication must be included in the differential diagnosis of pelvic cystic masses.