Clinical and Surgical Implications of Crossed Fusion Renal Ectopia Type E: A Case Report.

Crossed fused renal ectopia (CFRE) is a rare congenital anomaly in which one kidney crosses the midline and fuses with its contralateral counterpart due to abnormal migration during fetal development. Although often asymptomatic, associated anatomical variation may have important clinical and surgical implications. This report describes a rare CFRE Type E (L-shaped) identified during routine anatomical dissection. A 76-year-old male anatomical donor was found to have right-to-left renal ectopy with fusion at the inferior pole of the left kidney. The fused renal unit demonstrated complex vasculature, including five renal arteries and three renal veins with numerous tributaries. Two ureters were present with atypical positioning. The donor's medical history included hypertension, atrial flutter, hypothyroidism, and aortic insufficiency, with a self-reported history of bilateral pleural effusions, pneumonia, and renal cell carcinoma. While CFRE may not require intervention, the extent of vascular and ureteral variation observed in this case has direct implications for surgical planning, including nephrectomy, transplantation, and urologic procedures. Such variation may complicate intraoperative management if unrecognized. This case highlights a unique presentation of CFRE Type E with significant anatomical complexity. Recognition of such variants may improve diagnostic accuracy and surgical preparedness, and their inclusion in anatomical education may enhance clinical awareness among trainees.