IMMUNOHISTOCHEMICAL OBSERVATIONS ON A POSSIBLE AMELOBLASTIC FIBROODONTOMA

An ameloblastic fibro-odontoma which occurred in the mandible of a 3-y ear-old Japanese boy is reported together with immunohistochemical fin dings. Histologically, the tumor consisted of an ameloblastic fibroma- like area and some typical complex odontoma-like areas; The epithelial islands in the ameloblastic fibroma-like area showed different develo pmental stages of the epithelial-connective tissue interface. Immunohi stochemical examination revealed that all epithelial components in the ameloblastic fibroma-like area showed expression of CK 8, CKs 13, 16, CK 14, CK 18 and CK 19, and coexpression of these cytokeratins and vi mentin. These findings suggest that even the epithelial component with out obvious epithelial-mesenchymal induction showed the final cell dif ferentiation of the enamel organ with the potential for epithelial-mes enchymal induction.