[Immunohistochemical studies of chordomas and choroid tumors].

Chordomas are rare slow-growing but locally invasive tumors. They are thought to develop from residues of the notochord. Three chordomas and ten chondroid tumors were investigated by an indirect immunoperoxidase method for expression of the epithelial markers: MAM-6, keratin, tissue polypeptide antigen (TPA) and for carcinoembryonic antigen (CEA). In all the chordomas investigated the antigens MAM-6, keratin and TPA were detected using monoclonal antibodies and conventional antisera, respectively. These data provide further evidence of the epithelial nature and the ectodermal origin of chordomas. Moreover, the findings suggest that immunohistochemical methods may be useful for the differential diagnosis between chordomas and morphologically similar chondroid tumors.