A Rare Congenital Fused Kidney Anomaly in a 3-Year-Old Boy

Renal fusion is the second most common congenital anomaly of the kidney and the urinary tract, the first being duplication of the renal collecting system. Most patients are incidentally diagnosed during abdominal examination such as ultrasound, computed tomography, or magnetic resonance imaging. Renal fusion can accompany other anomalies and increases the incidence of urinary tract or systemic diseases. We report a 3-year-old boy who was initially diagnosed with a solitary kidney, which was then proved to be a rarelyseen variation of fused kidneys. We also discuss the further evaluation and prognosis of such a congenital anomaly.