Transverse fusion of the renal pelvis and single ureter.

We present a case of a rare renal anomaly in which the 2 kidneys (separate or fused across the midline) are drained by a common renal pelvis and ureter. Previously reported cases have been reviewed and are classified in 3 groups according to their anatomical features. The lesion is associated with some frequency with imperforate anus, sacral and other vertebral defects, neurogenic bladder, vesicoureteral reflux, upper tract dilatation, and urinary tract infections.