Abstract: Fourty-one patients with intracranial chordoma near the base of the skull (including 2 cases chondroid chordoma) are reported along with the clinical features and histopathology and ultrastructure character. This tumor had morphologic features identical to a chordoma: nodular growth with vacuolated cytoplasm and myxomatous stroma by light microscopy, positive immunoreaction for cytokeratin and epithelial membrane antigen by immunohistochemistry, desmosomes, microvilli mitochondria surround by rough endoplasmic reticulum by electron microscopy. The fine structure feature of chondroid chordoma was microtubules which located within the rough endoplasmic reticulum. The ultrastructural research confirmed that the chordoma presented not only epithelial differentiation but also mesenchymal. Some cells were multipotential neoplasms cells in which the stem cells were capable of differentiation along both epithelial and mesenchymal pathways. The results suggest the possibility of altered differentiation pathway of the tumor stem cell emergence of a new malignant cell population within the chordoma.

Key words: chordoma, ultrastructure, clinical research