PREOPERATIVE STAGE DIAGNOSIS BY ULTRASONOGRAPHY AND EVALUATION OF ECHO PATTERN ON RENAL CELL CARCINOMA

Abstract

Preoperative stage diagnosis of renal cell carcinoma is important to determine the treatment of choice. The present study reports the accuracy of preoperative tumor staging by ultrasonography in comparison to those by CT and angiography in 33 cases of renal cell carcinoma. The preoperative stagings were compared with operative or autopsy findings. The stages and grades were classified according to TNM classification by Japanese Urological Association.
As a result, the correct stage diagnosis could be made by ultrasonography in 15 of 21 pT2b cases and 2 of 7 pT3 cases. By angiography, 8 of 20 cases of pT2b were falsely dianosed. In pT4, ultrasonography and CT correctly staged all of the 5 cases extending to the neighboring organs. By the present study, ultrasonography could not be proved to be useful in the diagnosis of tumor thrombus into the renal vein and inferior vena cava (IVC), while CT seemed to be most useful to find metastasis to regional lymph nodes.
The correlation between echo patterns and prognosis was also studied in the same 33 cases. The echo patterns were classified into homogeneous or heterogeneous pattern according to echogenic homogeneity. Additionally, the homogeneous pattern was also analysed into hyperechoic, isoechoic, hypoechoic ones according to echo density of the tumor compared with that of renal parenchyma. Heterogeneous pattern was considered as mixed one which meant the coexistence of the other 3 patterns. The cases of mixed pattern appeared to coincide with higher grade and stage, lower survival rate and higher rate of distant metastasis than those revealing the other patterns. Pathological study showed the tumors of mixed pattern were more necrotic, hemorrhagic and fibrotic than those of the other patterns.
Conclusively, ultrasonographic findings were valuable in estimating not only preoperative stage diagnosis but also prognosis in renal cell carcinoma.