Sarcomatoid renal cell carcinoma with scant carcinomatous components

A 30-year-old male underwent radical nephrectomy for a right renal tumor 15 cm in diameter. On microscopic examination of initial 17 sections. the tum or consisted of pleomorphic giant cells and spindle neoplastic cells. There was no carcinomatous component. Immunohistochemically, the neoplastic cell s were negative for keratin and epithelial membrane antigen but positive fo r vimentin. The giant cells were also scatteringly, weakly positive for myo globin. At that time a diagnosis of rhabdomyosarcoma of the kidney was made . However, further microscopic examination of another eight sections reveal ed small areas of clear cell-type renal cell carcinoma (RCC) which transite d to sarcomatous components and led to a diagnosis of sarcomatoid RCC, The patient underwent three cycles of adjuvant chemotherapy. He has been free o f the disease for 14 months after nephrectomy.