Fine-needle aspiration biopsy in the preoperative diagnosis of chordoma: a study of 17 cases with application of electron microscopic, histochemical, and immunocytochemical examination.

The cytologic findings in a series of 17 patients with chordoma (one clivus, three cervical, one lumbar, and 12 sacral tumors), all of whom underwent fine-needle aspiration biopsy (FNAB) in the preoperative investigation, were studied. Cytologically, three main cell types were recognized: large, mononucleated or binucleated physaliferous cells with a vacuolated "bubbly" cytoplasm; small, rounded, uniform cells; and short spindle-shaped cells. The May-Grünwald-Giemsa staining was found superior to Papanicolaou staining in demonstrating the mucoid matrix and the vacuolated cytoplasm of the physaliferous tumor cells. Ultra-structurally, the tumor cells contained prominent bundles of filament of the intermediate type, as well as large vacuoles and lumina often bordered by microvillous projections; the cells were connected to one another by well-developed desmosomes. The resin embedding technique for the light and electron-microscopic examination of FNAB material (eight cases), the histochemical demonstration of sulphated glucosaminoglycans in the matrix (four cases), and the immunocytochemical analysis (four cases) with positivity for cytokeratin, epithelial membrane antigen, vimentin, and S-100 protein and negativity for carcinoembryonic antigen were found to be of value for the cytologic diagnosis of chordoma, and helped in distinguishing it from other chondrogenic tumors and metastatic mucous-producing carcinoma. From this study we conclude that a preoperative diagnosis of chordoma can be reached by FNAB, provided the findings are carefully evaluated in relation to the clinical and roentgenographic findings. Adjunctive histochemical, immunocytochemical, and ultrastructural techniques applied on the FNA material may be helpful in reaching a conclusive diagnosis when differential diagnostic problems occur.