Immunohistochemistry and lectin histochemistry in sarcomatoid renal cell carcinoma: a comparison with classical renal cell carcinoma

We investigated the expression of various cell markers in renal cell carcinoma, concentrating particularly on the sarcomatoid variety, using lectin and immunohistochemical techniques. The sarcomatoid variant showed stronger staining in a higher proportion of cases for vimentin and reduced positivity for epithelial membrane antigen, in comparison with classical renal cell carcinoma. All sarcomatoid tumours reacted with at least one cytokeratin, enabling them to be distinguished from true renal sarcomas; this is of diagnostic value when a panel of markers is used. Overall a similar pattern of markers is seen in sarcomatoid and classical renal cell carcinoma using lectin and immunohistochemistry, suggesting that the sarcomatoid variant arises as a metaplastic change rather than having a different histogenesis.