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

Thirty six cases of clear cell sarcoma of soft tissue are reported. The median 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 architecture was fascicular with lobular arrangement of cells delimited by delicate fibrous 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 9/10 HPF. S100 protein was expressed in 33/36 cases and HMB45 marked 29/31 cases, without expression of cytokeratin. Three-year and 5-year survival rate were respectively 72% and 62%. Prognosis factors for global survival were efficiency of initial treatment with distal location and necrosis and FNCLCC grade. The distinction of clear cell sarcoma from metastatic melanoma is important because of the difference of prognosis.