unusual presentation of renal cell carcinoma in crossed ectopic kidney

Introduction:crossed renal ectopia is a rare anomaly and ninety percent of crossed ectopic kidneys are fused to their ipsilateral mate. based on autopsy findings, the incidence has been estimated to be one in 2000 individuals.case presentation:we hereby report on a 53yearold woman with two episodes of painless gross hematuria. imaging revealed left side fused crossed renal ectopia and filling defect within the pyelocaliceal of crossed kidney.conclusions:the patient underwent surgery applying a midline incision. the left kidney showed a lump pattern embedded in lower pole of the right kidney. left sided nephrectomy was performed while temporary right renal artery was clamped temporarily. histopathological evaluation revealed clear cell carcinoma with severe nuclear atypia (fuhrman grade 4/4). however, local recurrence was not detected during the 18month follow up after surgery.