Mesenchymal chondrosarcoma is a rare tumor occuring both in bone and in soft tissues. It is a highly cellular primitive spindle-cell tumor displaying focal chondroid differentiation. A case of mesenchymal chondrosarcoma (15 years old male) with multicentric involvement both in femur and humerus before lung metastates is presented. It's multicentricity or unusual distant dissemination is discussed with literature survey.