CHONDROID CHORDOMA VERSUS LOW-GRADE CHONDROSARCOMA OF THE BASE OF THESKULL - CAN IMMUNOHISTOCHEMISTRY RESOLVE THE CONTROVERSY

The classification of cartilaginous tumors of the skull base, includin g chondroid chordoma and chondrosarcoma remains the subject of controv ersy. Critical review of the literature and our own experience of chor domas and cartilaginous tumors of the skull base led to the following conclusions: 1) Chondrosarcoma of the skull base is a distinct clinico pathological entity. The immunohistochemical staining pattern (cytoker atin negative, epithelial membrane antigen (EMA) negative) can be help ful in distinguishing it from chordoma with chondroid differentiation (cytokeratin positive, EMA positive). 2) The chondroid chordomas origi nally described by Heffelfinger et al, may have included some true cho ndrosarcomas with focal areas of myxoid chordomalike appearance. 3) Fo cal chondroid differentiation in chordoma is not such a rare phenomeno n. Further study is needed to define whether chordoma with chondroid f oci should be separated out from conventional chordoma as a distinct e ntity with a better prognosis.