I.V. Boulytcheva, T.V. Pavlenko, A.N. Machson

Chordomas and low-grade chondrosarcomas share many histological features, generating at times, considerable diagnostic difficulty and, not infrequently, requiring immunohistochemical analysis for appropriate classification. In an effort to clarify the diagnosis and differentiation with other cartilaginous tumors, 16 samples, obtained from 16 patients with chordoma were examined by immunohistochemistry with a panel of antibodies. The panel included antibodies to cytokeratin (CK), epithelial membrane antigen (EMA), D2-40, GFAP (glial fibrillary acidic protein), NSE (neuron-specific enolase), chromogranin, TTF-1 (thyroid transcription factor), PSA, CDX-2, mammaglobin. The conventional chordoma stained for CK (16/16) EMA (13/16), NSE (12/16) and was negative for chromogranin, GFAP. Specific markers were helpful in differential with metastatic carcinomas. Chordomas are difficult to excise because of their location and intimate relation to critical structures. Seven of 16 patients had recurrences, three of 16 patients had several local recurrences and progression with local effects.