Immunohistochemical and histochemical characterization of the mucosubstances of odontogenic myxoma: Histogenesis and differential diagnosis

To discuss the dental origin of odontogenic myxoma and to provide further i nformation for the differential diagnosis between this tumor and myxoid mal ignant fibrous histiocytoma (MFH) which occasionally occurs in jaw bones, t he contents of glycosaminoglycans (GAGs) and proteoglycans (PGs) in the muc osubstances of 15 odontogenic myxomas, 5 myxoid MFH and 3 human fetal tooth germs in the bell stage of development were characterized using histochemi cal and immunohistochemical methods. Histochemical staining of hyaluronic a cid (HA) was undertaken using biotinylated HA binding protein (B-HABP), and immunohistochemical detection was done using a panel of antibodies against chondroitin 6-sulfate (CS-6), chondroitin 4-sulfate (CS-4), dermatan sulfa te (DS), keratan sulfate (KS), heparan sulfate (HS), aggrecan, PG-M/versica n, decorin and biglycan. In odontogenic myxoma, CS-6, HA and PG-M/versican were observed in the myxomatous matrix of all cases, while KS and HS were s een in none. As for CS-4, DS, aggrecan, decorin and biglycan, only irregula r and mild stainings were shown. Consistent and strong positive straining f or CS-6, HA and PG-M/versican were seen in dental papilla and provided evid ence supporting the origin of this tumor from dental papilla. Except for th e constant staining for HA, the myxoid matrix was rarely stained for most G AGs and PGs in myxoid MFH. Immunodetection of CS-6 and PG-M/version with th e use of monoclonal antibodies 3-B-3 and 2-B-1 is therefore recommended as a useful tool in differentiating odontogenic myoma from myxoid MFH.