A Case of Type 1 Papillary Renal Cell Cancer with Pelvic Tumor Thrombus Masquerading as Urothelial Cancer with Review of Literature.

Adult renal tumors vary from renal cell carcinoma (RCC) to upper tract urothelial cancer (UTUC). Tumor characteristics such as renal vein and inferior vena cava tumor thrombus are usually seen with RCC, but tumor thrombus into pelvicaliceal system (PCS) is a rare entity in RCC. At present only 11 cases have been reported in the literature. We report an unusual case of papillary type 1 RCC in a young Muslim man mimicking as UTUC radiologically and found to have free tumor thrombus in PCS. At follow-up of 6 months after right nephroureterectomy with bladder cuff excision, he is doing well clinically and radiologically without any recurrence. RCC with tumor thrombus into PCS is an uncommon entity. It can give similar appearance as an urothelial cancer of the pelvis on radiologic imaging. Pelvic tumor thrombus is now considered as a factor of poor prognostic importance and rarely encountered with pure papillary type of RCC.