CLEAR-CELL ODONTOGENIC-TUMOR - A CASE WITH INDUCTION OF DENTIN-LIKE STRUCTURES

A case of clear cell odontogenic tumour, which occurred centrally in t he mandible of a 56-year-old Japanese woman, is reported with its hist ochemical, immunohistochemical and ultrastructural findings. Histologi cally, the tumour nests were composed of large glycogen-rich clear cel ls and small non-clear polygonal cells and were separated by thin matu re fibrous connective tissue septae. Immunohistochemically, both types of tumour cells showed positive expression of various cytokeratins, i n particular cytokeratin 19, and of epithelial membrane antigen. Eosin ophilic hyaline deposits and possible dentin-like structures were occa sionally formed in contact with the epithelial nests and are regarded as indicative of the epithelial-mesenchymal inductive capacity of this tumour. The aggressive nature of the present tumour was assumed throu gh its invasive growth pattern and occasional mitotic figures. Althoug h it was diagnosed as clear cell odontogenic tumour according to the p resent WHO classification, the patient must be followed carefully beca use of its probable malignant nature.