[Study on the pathological grade in the primary and distant metastatic lesions of renal cell carcinoma]

We studied the pathological features of renal cell carcinoma focusing on the changes of grade in the primary and metastatic lesions. The subjects consisted of 46 patients who received both nephrectomy and excision of distant metastatic lesions. As to the grade of metastatic lesions assessed according to the grade of primary lesion, over 40% of metastatic lesions did not coincide with the primary lesion except for grade I. In the study on the grade in each metastatic organ, as to lung metastasis, the rate of low grade malignancy (grades I and II) was 84.6%, and the same tendency was observed in the spleen (85.7%), adrenal gland of the affected side (71.4%), liver (100%) and brain (66.7%). On the other hand, as to the osseous metastasis, the rate of high grade malignancy (grades III and IV) was 87.5%, and the same tendency was observed in the contralateral adrenal gland (100%) and bladder (100%). We conclude that a lower grade clones as well as higher grade clones in the primary lesion must be analyzed to elucidate the metastasis of renal cell carcinoma.