Correlation among different pathologic features of renal cell carcinoma: a retrospective analysis of 249 cases.

Renal cell carcinoma (RCC) represents 90% of renal malignancies and is the most lethal neoplasm of the urologic system. RCC is not a single entity but rather a heterogeneous group of neoplasms with varying genetic, morphologic and clinical features and outcome. The aim of this study was to correlate pathologic features of RCC that can be helpful during the decision-making process. We present a retrospective analysis of 249 RCCs (203 clear cell, 32 papillary and 14 chromophobe RCCs). We found that 77.8% of tumors of ≤4 cm and only 28.8% of RCC of >7 cm were limited to the kidney. The likelihood of lymphovascular invasion, fibrous renal capsule/perinephric fat/renal sinus fat, and vascular infiltration increased dramatically with increasing tumor size, particularly over 4.5 cm. Fat tissue was more often invaded through the renal sinus than through the renal capsule. Nuclear grade was significantly related to the pT stage, tumor size, percentage of necrotic area, lymphovascular invasion, fibrous renal capsule/perinephric fat/renal sinus fat and vascular infiltration. Tumor size represents one of the most important factors determining biological behavior of renal cancer. Renal sinus and perinephric fat should be carefully investigated, particularly in case of tumors >4-5 cm. Despite increasing acceptance for partial nephrectomy in tumors >7 cm, these cancers invade renal sinus fat 11 times more often and perinephric fat 5.6 times more often than smaller ones.