Bilaterally Fused Supernumerary Kidneys: A Very Rare Case Report and Review of Literature

Supernumerary kidney is a rare anomaly of number where commonly a third extra kidney exists with its own collecting system, blood supply, and encapsulated parenchyma. However, an extremely rare and unique diagnosis of bilateral supernumerary kidneys is also reported in few instances where two extra kidneys exist on each side of the body. Parenchymal fusion and the presence of good excretory function make the supernumerary kidneys even rarer as many of the reported cases are rudimentary organs. We present a 35-year-old man with a sudden onset of agonizing right flank pain and tenderness. Radiologic assessment with computed tomography showed bilaterally fussed and malrotated supernumerary kidneys with an obstructive stone and good contrast uptake. The patient has four fully functional kidneys (two on each side) with their own arterial supply, venous drainage, collecting system and incompletely duplicated ureters bilaterally. An open pyelolithotomy is performed to relieve pain and hydronephrosis. The patient’s symptoms improved after surgery and during subsequent follow-up.