Clear cell sarcoma of soft tissue. Clinical, histopathological and prognostic study of 36 cases

Thirty six cases of clear cell sarcoma of soft tissue are reported The medi an age was 44 years (5 to 80 years). The principal sites were the foot (11 cases), the hand and wrist (7 cases) and the knee (6 cases). The architectu re was fascicular with lobular arrangement of cells delimited by delicate f ibrous septa intimately bound to tendons or aponeuroses. Tumoral cells were round or fusiform with abundant clear cytoplasm sometimes epithelioid with round nuclei and prominent nucleoli. The mitotic rate was evaluated to 9/1 0 HPF. S100 protein was expressed in 33/36 cases and HMB45 marked 29/31 cas es, without expression of cytokeratine. Three-year and 5-year survival rate were respectively 72 % and 62 %. Prognosis factors for global survival wer e efficiency of initial treatment with distal location and necrosis and FNC LCC grade. The distinction of clear cell sarcoma from metastatic melanoma i s important because of the difference of prognosis.