Horseshoe kidney with a retrocaval ureter.

Horseshoe kidney and retrocaval ureter are two uncommon congenital anomalies of the genitourinary system that have rarely been reported to occur in the same patient. In each case previously reported, the isthmus of the horseshoe was positioned posterior to the inferior vena cava and anterior to the aorta. In no case was the diagnosis of both anomalies made preoperatively. We report a case of simultaneous horseshoe kidney and retrocaval ureter diagnosed by preoperative imaging studies and discuss the diagnostic evaluation and surgical management of this rare entity.