Chordoma - A cytologic study with histologic and radiologic correlation

BACKGROUND. Chordoma is a rare malignant tumor of fetal notochord origin th at occurs along the spinal axis. The fine-needle aspiration biopsy (FNAB) f indings are described, correlated with histology and radiology, and compare d with previously reported descriptions of chordoma. METHODS. Fine-needle aspiration biopsies of 12 cases of chordoma with histo logic confirmation were reviewed. Imaging studies were reviewed in seven ca ses. Cytologic material included smears, ThinPrep, and cell blocks. Immunos tains were performed on selected cytologic and histologic specimens. Multip le cytologic parameters were studied. RESULTS. Eleven specimens were from the spinal axis, and one was from a che st wall metastasis. Ten cases were diagnosed as chordoma on cytologic mater ial, one was positive for malignancy with a differential diagnosis of chord oma and well differentiated chondrosarcoma, and one was positive for malign ancy, not further classified. Most smears were moderately to highly cellula r and demonstrated typical physaliphorous cells and a myxoid background. Tw o of the 10 cases diagnosed as chordoma showed pleomorphic physaliphorous c ells, nuclear inclusions, and binucleation. Nuclear inclusions were observe d in three other cases diagnosed as chordoma. Histologic follow-up of one c ase with pleomorphic physaliphorous cells showed conventional chordoma with focal areas of increased cellularity and pleomorphism. Pleomorphic sarcoma tous cells were the predominant cell type in one case that showed dediffere ntiated chordoma histologically. Mitotic figures were rarely observed in cy tologic material. CONCLUSIONS. Cytomorphologic features of chordoma allow accurate diagnosis by FNAB. Features associated with dedifferentiation include increased pleom orphism of physaliphorous cells and may include nuclear inclusions, bi- or multinucleation, and rarely, mitotic figures. Cancer (Cancer Cytopathol) 20 01;93:40-51. (C) 2001 American Cancer Society.