The morphological characteristics and immunophenotype of renal cell carcinomas with eosinophilic cytoplasm

Abstract

to investigate the morphological and immunophenotypic features of rare types of renal cell carcinomas with eosinophilic cytoplasm. An investigation was conducted using a surgical material from 294 patients with a kidney tumor. An immunohistochemical (IHC) study was performed on paraffin sections according to the standard protocol using a wide panel of antibodies. Based on a morphological analysis and IHC study, the tumors were divided into 3 groups: 1) 127 (43%) oncocytic tumors that expressed classical IHC markers for oncocytoma and chromophobe renal cell carcinoma; 2) 50 (17%) oncocytic tumors that did not correspond to the immunophenotypes of oncocytoma and chromophobe renal cell carcinoma; and 3) 117 (40%) eosinophilic cellular nononcocytic renal tumors. With the advent of the current differential diagnostic criteria, the classification of renal cell carcinomas continues to expand. To date, a hybrid oncocytic/chromophobic tumor, eosinophilic solid and cystic renal cell carcinoma, and follicular kidney cancer should be regarded as new nosological entities.