Chromophobe renal cell carcinoma with sarcomatoid transformation

We present a rare case of a chromophobe renal cell carcinoma that progressed to a high-grade spindle cell sarcoma. The tumor affected a 50-year-old man who had presented with right upper quadrant discomfort and hematuria and subsequently underwent a right radical nephrectomy. Microscopically, the tumor was composed of two distinct components, a chromophobe renal cell carcinoma and a sarcomatoid component. The sarcomatoid component had exhibited aggressive behavior by spreading to a regional lymph node. This case report shows that chromophobe carcinoma can develop a sarcomatoid transformation with a high propensity for invasive growth and metastasis.