Chondroid chordoma: fine-needle aspiration cytology with histopathological, immunohistochemical, and ultrastructural study of two cases.

Chondroid chordoma is a controversial and confusing entity that was originally described by Heffelfinger et al. (Cancer 1973; 32:410-420) as a biphasic malignant neoplasm possessing elements of both chordoma and cartilaginous tissue. Fine-needle aspiration (FNA) cytology of chondroid chordoma has not been described. The aim of our investigation was to characterize the chondroid area of chondroid chordoma and to compare the FNA features with those of well-differentiated chondrosarcoma. Clival and cervical spine chondroid chordomas were studied with light microscopy, immunohistochemistry, and electron microscopy. Chondroid chordomas demonstrated an epithelial nature by immunohistochemistry and ultrastructural studies. The FNA smears showed low cellularity, with loosely arranged or dispersed round cells in a myxoid background. Although the smears were similar to those of well-differentiated chondrosarcomas, they showed a positive reaction for epithelial markers. These findings reveal that chondroid chordoma is a variant of chordoma which possesses a hyaline matrix. Immunohistochemical demonstration of epithelial markers is useful to distinguish it from chondrosarcoma. Diagn. Cytopathol. 1999; 21:335-339.