[Four cases of sarcomatoid renal cell carcinoma]

We herein report four cases of sarcomatoid renal cell carcinoma. These cases comprised 4.1% of the 98 patients with renal cell carcinoma treated in our department during the past 13 years. It is confirmed that renal cell carcinoma with a sarcomatoid component often shows local invasion, distant metastasis, rapid growth and poor prognosis. In Mian's series, the percentage of sarcomatoid component (< 25% vs > or = 25%) was associated with decreased survival time, but was independent of stage. The pathological stage was pT3b N0 M0 in case 1, pT1b N0 M1 in case 2, pT3b N0 M1 in case 3 and pT1a N0 M1 in case 4. The pT1 sarcomatoid renal cell carcinoma in case 2 and case 4, who developed poor prognosis, was composed of 60 and 80% sarcomatoid change, respectively. However in case 3 with a pathological stage of pT3, the patient is alive 35 months after resection, because the extent of sarcomatoid component was 25%. The prognosis of patients with sarcomatoid renal cell carcinoma depends on not only disease stage and tumor grade but also the pathological extent of sarcomatoid component.