[A clinicopathological and immunohistochemical study of 34 cases of chordoma].

Unlabelled: In order to investigate the clinicopathological and immunohistochemical features of chordomas, 34 chordomas, with 5 chondrosarcomas for comparison, were studied by clinicopathological and immunohistochemical methods.
Results: Based on the presence or absence of cartilaginous areas, chordomas are classified into two subtypes: chondroid chordoma (14 cases) and classic chordoma (20 cases). Chondroid chordoma occurred in a younger age group (mean age 40.9 years) than classic chordoma (mean age 51.1 years). 7/14 (50%) of chondroid chordomas occurred in the sacrococcygeal region, 4/ 14 (28.6%) occurred in the spheno-occipital region. Immunohistochemical staining showed that all chordomas were positive for cytokeratin, and 16 (47.1%) chordomas were also positive for EMA. In contrast, 5 chondrosarcomas were immunonegative for both cytokeratin and EMA. Vimentin and S-100 protein were positive in the majority of chordomas (29 & 24 respectively) and in the 5 chondrosarcomas. The present study confirms the dual features of chordoma-epithelial and mesenchymal, and also the utility of immunohistochemical staining in the differential diagnosis of chordoma and chondrosarcoma. The pathologic diagnosis of chondroid chordoma and other issues were also discussed in the study.