[Clinicopathological study on patients with renal cell carcinoma according to whole area histological sections]

We tried to establish new classification of histological grade and indication of elective nephron-sparing surgery (ENSS) in renal cell carcinoma (RCC), and studied histological changes according to tumor size.

We made whole area histological sections on 142 cases with RCC and investigated histological aspects and prognosis.

(1) To classify the grade of the cases, the worst grade which occupied more than 10% of the tumor provided most appropriate prognosis. (2) In 144 cases (kidneys), satellite tumor lesions (STL) were observed in 69 cases (47.9%), and the cases with vein invasion were observed in 75 cases (51.4%). Incidence of these two factors increased with tumor size. (3) From the point of view of location of STL and vein invasion, ENSS was possible with taking more than 2 cm surgical margin in the cases with less than 4 cm in size and slow growing type. But indication of ENSS should not be decided with ease. (4) Incidence of the cases with multiple structural and cell types and grades increased with tumor size. (5) Incidence of the cases with solid structure, spindle or pleomorphic cell type and high grade increased with tumor size. (6) It was supposed that tumor heterogeneity and progression could be associated with tumor growth in each cases.

These results suggest the necessity of treatment of the cases with RCC as small as possible. If the tumor is less than 4 cm, prognosis tends to be good, and ENSS might be possible in some cases.