Unveiling the Unexpected: A Case of Crossed Fused Renal Ectopia in a Young Woman

Crossed fused renal ectopia is a rare congenital anomaly where one kidney crosses the midline and fuses with the contralateral kidney, occurring in 1 in 2000 births. Most cases are asymptomatic and discovered incidentally. We report an 18-year-old female who presented with left-sided loin pain. Physical examination showed left lumbar tenderness, with normal laboratory results. An abdominal ultrasound failed to visualise the right kidney, suggesting a crossed-fused ectopia. Further evaluation with CECT-KUB confirmed that the right kidney was fused to the left without any associated complications. The patient was managed conservatively with regular follow-up. Diagnosis typically requires cross-sectional imaging. Asymptomatic patients do not need intervention. However, surgical planning requires caution due to abnormal vascular patterns, and angiography is recommended before any procedures.