[Sarcomatoid renal cell carcinoma: a case report].

A 75-year-old male presented to our hospital with a complaint of macroscopic hematuria. Laboratory examinations in peripheral blood showed slight anemia and the increase of acute phase reactants (c-reactive protein, immunosuppressive acidic protein, alpha 2-globulin). Abdominal enhanced computerized tomography revealed a huge tumor with calcification at the upper pole of the right kidney. Magnetic resonance imaging (MRI) showed a low intensity mass at the upper portion of the right kidney on T2-weighted sequences. The right radical nephrectomy was performed and the histopathological diagnosis was sarcomatoid renal cell carcinoma because of positive immunohistochemical staining for vimentin and negative for cytokeratin. Because sarcomatoid type has a highly malignant behavior and poor prognosis among renal cell carcinomas, an adjuvant treatment which is effective in controlling the disease is awaited.