Morphologic typing of papillary renal cell carcinoma: Comparison of growthkinetics and patient survival in 66 cases

Whereas papillary renal cell carcinoma is now established as a subtype of r enal cell neoplasia, division of these tumors into 2 distinctive morphotype s has been proposed. Type I tumors have cells with scanty pale cytoplasm ar ranged in a single layer on the basement membrane of papillary cores. In th ese tumors, psammoma bodies and foamy macrophages are frequently seen, and the tumors frequently express cytokeratin 7. Type 2 tumor cells have pseudo stratified nuclei and usually have voluminous eosinophilic cytoplasm. Recen t studies have supported this subclassification of papillary renal cell car cinoma by demonstrating differing genotypes for type 1 and 2 tumors. To fur ther study the subclassification of papillary renal carcinoma, we compared clinical features, nuclear grade, stage, tumor growth kinetics, and surviva l in a series of 50 type 1 and 16 type 2 papillary renal cell carcinomas. C omparison of patient age at presentation, sex, and primary tumor size shows no significant difference between the 2 tumor types. Type 1 tumors were of significantly lower Fuhrman grade (P = .0001) and higher Robson stage (P = .009) than type 2 tumors. There was no significant difference when tumors were staged according to the TNM classification. Assessment of tumor growth kinetics showed significantly different mean silver-staining nucleolar org anizer region (AgNOR) scores and Ki-67 indices (AgNOR type 1, 3.83, type 2, 7.24, P = .0001; Ki 67 type I, 3.17%, type 2, 6.01%, P = .0002). Multivari ate analysis showed tumor type (P = .03), presence of metastases (P = .04), AgNOR score (P = .001), and Ki-67 index (P = .03) to be independently asso ciated with survival. These results provide evidence of the clinical utilit y of dividing papillary renal cell carcinomas into 2 types according to his tologic characteristics. Copyright (C) 2001 by W.B. Saunders Company.