The classification of cartilaginous
tumors of the skull base, including chondroid
chordoma and
chondrosarcoma remains the subject of controversy. Critical review of the literature and our own experience of
chordomas and cartilaginous
tumors of the skull base led to the following conclusions: 1)
Chondrosarcoma of the skull base is a distinct clinicopathological entity. The immunohistochemical staining pattern (
cytokeratin negative,
epithelial membrane antigen (EMA) negative) can be helpful in distinguishing it from
chordoma with chondroid differentiation (
cytokeratin positive, EMA positive). 2) The chondroid
chordomas originally described by Heffelfinger et al. may have included some true
chondrosarcomas with focal areas of myxoid chordomalike appearance. 3) Focal chondroid differentiation in
chordoma is not such a rare phenomenon. Further study is needed to define whether
chordoma with chondroid foci should be separated out from conventional
chordoma as a distinct entity with a better prognosis.