In 1973, Heffelfinger and coworkers described a variant of
chordoma that contained cartilaginous areas indistinguishable from hyaline type
chondrosarcoma. They designated these
tumors chondroid
chordomas and found that they had a better prognosis than classic (nonchondroid)
chordomas. Since that time, there has been an ongoing debate over whether chondroid
chordoma is best considered a distinct clinicopathologic entity separable from
chondrosarcoma or a misdiagnosed
chondrosarcoma whose concept developed from the erroneous interpretation of morphology. In an attempt to clarify the issue, the authors used light microscopy and immunohistochemistry to study 12 chondroid
chordomas, 38 classic
chordomas, and 28
chondrosarcomas that arose in the base of the skull or spine. As a reference, they also analyzed the immunohistochemical profile of fetal notochord, ecchordosis physaliphora, and fetal hyaline cartilage. They found that all chondroid and nonchondroid
chordomas were positive for
cytokeratin, and the majority were also positive for
epithelial membrane antigen (EMA) and
carcinoembryonic antigen (CEA). In contrast, none of the
chondrosarcomas stained for
cytokeratin, EMA or CEA.
Vimentin and S-100 were positive in more than 95% of both classic and chondroid
chordomas and
chondrosarcomas. The immunohistochemical profile of these
tumors was similar to the pattern of immunoreactivity of their nonneoplastic counterparts. The authors conclude that chondroid
chordomas is a variant of
chordoma and should not be confused with
chondrosarcoma. Because chondroid
chordomas have been reported to have a better prognosis, they felt that this nosologic term should be preserved and that chondroid
chordoma should continue to be a focus of clinical and pathologic study.