For distinction of oncocytoma and chromophobe renal cell carcinoma from other renal cell carcinoma subtypes, such as clear cell and papillary renal cell carcinoma variants with eosinophilic cytoplasm, markers such as KIT (CD117) and vimentin may be helpful, as both oncocytoma and chromophobe renal cell carcinoma share frequent membranous positivity for KIT and negative staining for vimentin, in contrast to clear cell and papillary renal cell carcinoma, which characteristically have the opposite findings (negative KIT and often positive vimentin) (11, 17). This evidence concerns the gene KIT and oncocytic adenoma.