Sarcomatoid carcinoma of the kidney.

Among 315 cases of parenchymal renal carcinoma resected between 1975 and 1985, 19 cases (6 per cent) of sarcomatoid carcinoma were identified. All patients were symptomatic or had a palpable mass in the flank at hospitalization. Tumor stage generally was advanced at operation and metastases were detected in 8 patients (Robson stage IV), all of whom died after an average postoperative survival of 8 months. In 3 patients there was tumor invasion of the renal vein (Robson stage IIIA), and they died after an average postoperative period of 11 months. Of 4 patients with perinephric fat invasion (Robson stage II) 2 died of cancer after an average survival of 15 months and 2 are alive with no evidence of disease for an average of 73 months postoperatively. In these later 2 cases the sarcomatoid areas constituted less than 5 per cent of the entire tumor and the remaining tumor was low grade carcinoma. In 3 patients adequate followup is not available and 1 was lost to followup. This histological variant of parenchymal cell carcinoma is a high grade malignancy with a poor prognosis. Operative treatment appears to be ineffective in modifying the behavior of the tumor.