Assessment of Perirenal Fat Infiltration in Renal Cell Carcinoma by CT

Abstract

Forty-two preoperative CT scans with renal cell carcinoma were reviewed and compared with pathologic findings to evaluate the differential points between stage I and II. Regardless of whole body staging, perirenal fat infiltrations were seen in 9 cases and the other 33 cases showed no infiltration onto perirenal fat tissue. We retrospectively reviewed them by comparing tumor size and CT findings, following three view points, lobulating contour of tumor margin, thickening of Gerota's fascia and strands in perirenal fat tissue. The size of them was 2-15 cm, size of the stage I tumors was 2-15 cm and that of stage II was 6-15 cm. In stage I(n=33), 25 cases(76%) showed smooth margin, and the others(n=8) showed lobulating contours. Thickening of Gerota's fascia was observed in 7 cases(21%) and strands in perirenal fat tissue in 14(42%). Of these, only one positive finding was seen in 7 cases(21%), 2 findings in 6(18%), 3 findings in 3 (9%) and nothing in 17cases(51%). In stage II(n=9), 3 cases(34%) showed smooth margin, and the others(n=6) showed lobulating contours. Thickening of Gerota's fascia were observed in 5 cases(55%) and strands in perirenal fat tissue in 9(100%). Of these, one finding was seen in 2 cases(22%), 2 findings in 3(33%), 3 findings in 4 (44%). In conclusion, it is insufficient to evaluate the perirenal fat infiltration in renal cell carcinoma with only one positive finding of 3 view points; lobulation of tumor margin, thickening of Gerota's fascia, strands in perirenal fat tissue. But if all these findings are shown, it is helpful to determinate perirenal fat infiltration of renal cell carcinoma.