Objective To investigate the clinical characteristics of primary adult renal sarcoma.  Methods A total of 1654 cases with adult renal tumors were treated during 1985 to 2009 in Peking Union Medical College Hospital. Of all

17 cases were diagnosed as primary renal sarcoma and underwent radical nephrectomy. The clinical features of 17 such patients were retrospectively analyzed.  Results The first symptom of 10 (59%) cases in all renal sarcomas was abdominal mass. The pathological diagnosis was leiomyosarcoma (7 cases)

rhabdomyosarcoma (2 cases)

malignant fibrous histiocytoma (2 cases)

low-differentiated sarcoma (2 cases)

chromophobe renal cell carcinoma coexisting with liposarcoma (1 case)

fibrosarcoma (1 case)

embryonic sarcoma (1 case) and leiomyosarcoma (1 case). One patient died of tumor thrombus of the inferior vena cava during surgery. Finally

15 cases were regularly followed up for 4 to 60 months. Till now

1 had tumor-free survival for 9 months

and the other 14 cases died 2-38 months after the operation with a median survival time of 18 (range

5-60) months. The median survival time of leiomyosarcoma group was 28 (range

11-60) months

and 2 cases of malignant fibrous histiocytoma died 4 and 8 months after the operation respectively. Conclusions The primary renal sarcoma has the clinical symptom similar with advanced renal cell carcinoma and has poor prognosis. Leiomyosarcoma might have relative good prognosis.