[Mesenchymal chondrosarcoma. Anatomico-clinical, immunohistochemical and ultrastructural study. Apropos of a case].

One case of mesenchymal chondrosarcoma of the mandible is reported in a 18 years-old man. The patient noted swelling and pain and roentgenography showed an osteolytic lesion of the right mandible. Histologically, the feature was obvious with chondroid sheets of round ovoid or elongated cells. Immunohistochemically, numerous cells had positive S-100 protein and vimentin. The electron microscopy showed numerous undifferentiated cells and also fibroblastic and cartilaginous cells. The prognosis of this tumor, usually bad, cannot be yet appreciated in this case (follow-up of only 3 months). The histogenesis of this peculiar variety of chondrosarcoma is discussed.