RESUMEN
Clear cell sarcoma [or malignant melanoma] of soft parts is a rare malignancy that is found in the young adults and is generally located in the extremities of the limbs. In this study, we report a new case diagnosed in a 23-year old male revealed by a slowly enlarging mass of the knee. The histopathologic pattern of the mass was composed of nests and stands of fusiform or round cells alternating with bands of sclerotic stroma. The tumoral cells presented abundant, eosinophilic and sometimes clear cytoplasm. Some cells contain brown pigment which is Fontana [+]. Vimentin, S100 protein and HMbeta45 antibodies were expressed by the tumoral cells confirming the diagnosis of soft tissue clear cell sarcoma. Large surgical resection was performed with no recurrence eight months after