Supernumerary kidneys--a rare anatomic variant.

Supernumerary kidneys are a rare congenital anomaly with fewer than 100 cases reported over the years. A fused supernumerary kidney is a still rarer entity. We present imaging findings in two cases of supernumerary kidneys--the first case is a spectacular image of four kidneys in one patient seen in an excretory phase of intravenous urogram with only four cases described in the literature. The second case is that of three kidneys (fused supernumerary) seen in another patient.