Chromophobe renal cell carcinoma with heterologous (liposarcomatous) differentiation: a case report.

A 44-year-old woman presented with right flank mass of 6 months duration. A right side renal tumor was diagnosed, and a radical nephrectomy was performed. Histopathological examination showed chromophobe renal cell carcinoma (CRCC) with sarcomatoid transformation. The sarcomatous component contained large pleomorphic lipoblasts. The CRCC was positive for Hale's colloidal iron stain, whereas the sarcomatous component was negative. Based on histopathological and immunohistochemical findings, a diagnosis of sarcomatoid CRCC with heterologous liposarcomatous differentiation was made. To the authors' knowledge, this is the second reported case of a sarcomatoid CRCC where the sarcomatous component displayed features of liposarcoma. The case has been reported for its rarity.