Osteosarcomas and chondrosarcomas of the jaws: immunohistochemical correlations.

Clinical, microscopic, and immunohistochemical characteristics of 17 jaw sarcomas are reported. Histologic subtypes included chondroblastic (five), fibroblastic (five), osteoblastic (three), telangiectatic (one), parosteal (two), and chondrosarcoma (one). Reactivity for all antigenic markers in decalcified tissue was judged to be comparable to nondecalcified tissue. All neoplasms were nonreactive for muramidase and leukocyte common antigen. alpha-1 Antichymotrypsin and HLA-DR immunoreactivity was found focally. Positive S-100 staining was found predominantly in chondrocytes. All tumors were positive for vimentin. Cells in focal zones of cartilage were positive for keratin. No distinctive pattern emerged relative to clinical recurrence and histologic subtype or immunotype. Leukocyte common antigen determinations were useful because they distinguished between neoplastic and inflammatory cells. S-100 protein stains helped in the subclassification of chondroblastic osteosarcoma, and vimentin stains confirmed mesenchymal origin. Cross-reactive staining of cartilage with keratin antibodies was regarded as a possible diagnostic pitfall.