[Clear cell sarcoma of soft tissues: a case report].

Clear cell sarcoma or melanoma of soft tissues is a rare tumor in young adults, mainly located in the extremities. We report a new case observed in a 15-year-old teenager who had injured her left knee 1 month before hospitalization. The patient consulted for deformation of the left knee with pain and limitation in flexion. A CT scan of the knee showed a hypodense mass of the anterior compartment of the left leg. The histological and immunohistochemical study of the biopsy fragment concluded in clear cell sarcoma of the soft tissue. The histogenesis of this tumor continues to be debated and raises diagnostic challenges for the pathologist who must eliminate melanoma metastases, whose prognosis is different.