Chromophobe renal cell carcinoma with sarcomatoid and heterologous osteosarcoma-like differentiation: a case report and literature review.

Chromophobe renal cell carcinoma (CRCC) is a subtype of renal cell carcinoma (RCC) with a favorable prognosis. Sarcomatoid differentiation in RCC is assumed to be the outcome of the parent tumor's dedifferentiation and associated with poorer prognosis. Sarcomatoid differentiation can be detected in CRCC as well as other subtypes, but the occurrence of divergent osteosarcoma-like components in sarcomatoid CRCC is extremely unusual.