Retroaortic Variant of Reverse Horseshoe Kidney With Butterfly Vertebrae Presenting as Neurogenic Bladder

Horseshoe kidney is a relatively common congenital anomaly. In 95% of the cases, lower poles are connected to each other. In a small subset, an isthmus connects both upper poles (reverse horseshoe kidney). Almost always, the fusion of kidney poles occurs anterior to the aorta and vena cava. The fusion of renal poles posterior to both aorta and vena cava is extremely rare. Herein, we present a case with multiple rare congenital anomalies-retroaortic variant of reverse horseshoe kidney, retroaortic left renal vein, and butterfly vertebrae.