Immunohistochemical and electron microscopic studies on intracranial chordomas: difference between typical chordomas and chondroid chordomas.

Immunohistochemical and electron microscopic studies were carried out on 9 cases of intracranial chordomas. Three of them were typical chordomas and 6 were chondroid chordomas. Immunohistochemically, both typical chordomas and chondroid chordomas were positively stained for cytokeratin and epithelial membrane antigen. Chondroid chordomas were stained for vimentin with moderate intensity whereas typical chordomas were only slightly stained. In comparison to typical chordomas, the chondroid chordomas had relatively few desmosomes and intermediate filaments. These findings suggest that intracranial chordomas are of mixed epithelial-mesenchymal nature, and that chondroid chordomas have a predominant mesenchymal character as compared to typical chordomas.