[Chordomas].

Chordomas are slowly growing malignant tumors arising from notochordal rests. They are occurring in adults (50 to 60 year old) and are mainly (85%) located in sacrococcygeal or spheno-occipital regions; other main localization is cervical spine. Chordomas are usually discovered in patients with pain or symptoms due to compression of surrounding viscera. Radiologically it is characterized by association of osteolysis and soft tissues opacity. On macroscopic examination tumoral tissue has mucoid appearance; under microscope it is made up with lobules of epithelial-appearing cells surrounded by acid mucosubstances. Tumorous cells contain glycogen and neutral mucosubstances. They are surrounded by argyrophilic rim due to pericellular condensation of intercellular matrix, well viewed on electron microscope examination. When their cytoplasm is filled with vacuoles, cells take up typical physaliphorous appearance. Chordomas cells express epithelial differentiation antigens (low molecular weight cytokeratins, EMA, CAM 52, HFM 62, even CEA), Vimentin and S-100 Protein: this triple positivity allow differentiation between chordomas and numerous others tumors. Correct treatment of chordoma is achieved with an initially complete excision. Local recurrences are frequent and sometimes inoperable: in this cases radiotherapy alone may be performed (70 grays). Sarcomas (fibroblastic or Malignant fibrous histiocytoma) may occur after radiotherapy or without it. Hematogenous metastasis occur in 10% to 15% of patients. Survival rate at five years is included between 50% and 75%. Chondroid chordoma is a special entity occurring in younger patients (35 year old) and located in spheno-occipital region. In addition to chordomas it contain chondroid (benign or malignant) islands. Mean survival rate (16 years) is far better than for chordoma or chondrosarcoma.