[Sarcomatoid variant of chromophobe renal cell carcinoma. Report of 2 cases]

In this paper, we report two cases of sarcomatoid carcinoma arising in chromophobe carcinoma. The sarcomatoid component appeared as white, shiny areas, occupying less than 10% of each tumor and containing numerous mitotic figures. Whereas both components expressed cytokeratin, only the carcinomatous cells were positive for epithelial membrane antigen and only the sarcomatoid cells were found to express vimentine. Sarcomatoid transformation in chromophobe cell carcinoma has been reported exceptionally. An aggressive behavior may be expected. The variable proportion of sarcomatoid component may lead to multiplication of the samples, especially when white, firm and shiny areas are detected on gross findings.