Angiographic, surgical, and pathologic observations of 70 patients with single hypervascular renal cell carcinomas were reviewed. To correlate size and location with extension into the renal veins or inferior vena cava, the tumors were divided into 3 groups on the basis of size. Of the 32 group I tumors (3-5 cm), 4 showed venous extension. Three involved only the right renal vein, while 1 extended through the right renal vein into the inferior vena cava. Of the 24 group II tumors (5-7 cm), 12 showed venous extension. Only 1 of these was confined to the right renal vein, while 11 extended through the renal vein into the inferior vena cava. Eight of the 13 group III tumors (greater than 7 cm) showed venous extension. Three of these were confined to the renal vein, while 5 extended through the right renal vein into the inferior vena cava. This investigation indicates that venous extension is more frequent with tumors of the right kidney and with tumors of larger size.
