Right Renal Pelvis Renal Cell Carcinoma Mimicking Transitional Cell Carcinoma: Case Report.

Background: Renal cell carcinoma (RCC) originates from the renal parenchyma, whereas transitional cell carcinoma (TCC) originates from the renal urothelium. Although renal pelvis TCC is relatively rare in terms of urologic malignancies, it is the most common tumor originating in renal pelvis. Case presentation: A 75-year-old woman presented with gross hematuria found to have a filling defect in the renal pelvis with retrograde pyelogram and cytology showed clusters of urothelial cells, with imaging suspicious for TCC. Patient underwent robotic nephroureterectomy with partial cystectomy. Pathology analysis revealed RCC. Conclusion: RCC may occur in the renal pelvis mimicking TCC. Extensive preoperative evaluation to accurately diagnose tumor is key to avoid unnecessary procedures. Intraoperative pathologic evaluation is emphasized with inconclusive preoperative results.