[Significance of immunohistochemical study in the diagnosis and differential diagnosis of chordoma].

Seven cases of chordoma were studied immunohisto-chemically with antibodies directed to epithelium, nerve, mesenchyme, muscle and histiocyte. Six cases of chondrosarcoma and three cases of mucinous carcinoma of colon were studied as control. The results showed that the chordomas were positive for cyto-K 6/7, EMA 7/7, CEA 6/7, Vim 7/7, S-100 7/7, alpha-AT 7/7, Lyso 4/7, while negative for GFAP and Des in all 7 cases indicating that chordoma, just like notochord, had the potentiality of multidirectional differentiation. In contrast, none of the chondrosarcomas was positive for cyto-K, EMA or CEA, but positive for Vim and S-100 in 6 cases. Three cases of colon mucinous carcinoma were positive for epithelial antibodies, but none reacted with other antibodies. Thus, immunohistochemical studies are of help in the diagnosis and differential diagnosis of chordoma.