This male pt. with flank pain, hematuria and demonstration of a solid renal mass is having renal cell carcinoma (in clinical practice any solid renal mass is considered RCC until proved otherwise) For patients with bilateral RCCs, paial nephrectomy with an adequate parenchymal margin is the preferred approach for kidney with the smaller lesion. Paial nephrectomy or Nephron-sparing procedures are found to be equally effective on radical nephrectomy if the tumor size is less than 4 cms. Ref : Smith's Urology 17/e p336