Sarcomatoid renal cell carcinoma with foci of chromophobe carcinoma.

Both chromophobe carcinoma and sarcomatoid carcinoma of the kidney are rare. The former is characterized by a relatively good prognosis, while the latter is a highly aggressive tumor. Coexistence of the two components in one renal tumor, which has been reported only rarely, is therefore paradoxical. Both sarcomatoid and chromophobe renal carcinoma were diagnosed in a 52-year-old woman following nephrectomy and resection of metastases in the right lobe of the liver. She died of the disease two months after the first operation; only the sarcomatoid component of her tumor was seen in the liver metastasis and the recurrent carcinoma. Differences in phenotype, immunophenotype and DNA-ploidy patterns of the two components are reported. The intensive p53 staining observed only in the sarcomatoid area supports the role of the TP53 gene in the transformation of chromophobe renal carcinoma to sarcomatoid carcinoma.