[Multicentricity and concomitant tumors in renal cell carcinoma: analysis by serial section of resected kidneys]

Nephron-sparing surgery was initially limited to the patients with localized renal cancer (RCC) present bilaterally or in a solitary kidney. Recently there is controversy in the indication for partial nephrectomy or enucleation to incidentally defined small RCC with normal opposite kidney. We examined the incidence of multicentricity in 43 kidneys removed for RCC with a diameter of less than 80 mm. The mean diameter of the predominant tumors was 45 mm (range 12 to 80 mm). The kidneys were serially sectioned at 5 mm intervals. Three of 43 kidneys (7%) had multiple RCC. The size of the concomitant tumors ranged from 2 to 15 mm. The multicentricity had no relation to pathological grade, stage, vascular invasion or infiltration pattern. In addition, the other 4 kidneys had 2 adenomas, 1 angiomyolipoma and 1 fibroma. Therefore we observed a 16% incidence of small renal nodules and a 7% multicentricity of RCC in the nephrectomized kidneys with normal opposite kidney.