DOI: https://doi.org/10.36347/sjmcr.2025.v13i10.081

Pages: 2526-2529

Supernumerary kidney is an extremely rare congenital anomaly, defined by the presence of an additional kidney with its own capsule, blood supply, and collecting system. Even more unusual is the occurrence of a supernumerary kidney associated with a fusion anomaly such as a sigmoid kidney, in which the renal units are joined in an S-shaped configuration. We report the case of a 33-year-old woman in whom a supernumerary kidney forming a sigmoid fusion pattern was identified an abdominal CT performed for abdominal pains accentuated in the lumbar area. Imaging demonstrated three renal units, with the lower supernumerary kidney fused to the contralateral kidney in a sigmoid arrangement, each possessing its own collecting system and vascular supply. No associated obstruction, calculi, or infection were observed. Recognition of such rare anomalies is important, as they may be mistaken for renal or retroperitoneal masses and can present significant challenges during surgical or interventional procedures. This case contributes to the limited literature on supernumerary kidneys with sigmoid fusion and underlines the value of detailed radiological evaluation for accurate diagnosis and management planning.