Chondroid chordoma.

We reject the notion that the concept of "chondroid chordoma" be abandoned in favor of an interpretation of the cartilaginous origin of these lesions. We have demonstrated by electron microscopic and immunohistochemical means that these neoplasms can exhibit distinctly epithelial characteristics in their chondroid as well as their epithelial areas. The presence of desmosomes, cytokeratin, carcinoembryonic, and epithelial membrane antigen in the cells of the chondroid as well as the epithelial areas; the presence of the microtubular inclusions, vimentin, and S-100 protein in the cells of the epithelial as well as chondroid areas; and the intermingling of the two and gradual transitions from one to the other all point to the conclusion that the chondroid and epithelial areas are only differing morphologic expressions of the same entity. The gradual evolution witnessed in the sequential biopsies of this case study, through which a predominantly chondromatous neoplasm became a chordoma of typical histologic appearance, provides further strong evidence to support the contention that chondroid chordoma is a variant of chordoma and not a primary chondrocytic neoplasm.