Computed tomography appearance of fused (horseshoe) kidney

Horseshoe kidneys occur approximately once in every 400-500 births. We present three cases of renal fusion anomalies with their computed tomography scans. In patients with little retroperitoneal fat the presence of a renal fusion anomaly can mimic a retroperitoneal mass. Horseshoe kidneys can be suspected by the characteristic anteromedial placement of the renal hilar structures and by enhancement after contrast infusion. An intravenous pyelogram will confirm the finding.