| dc.description.abstract | The purpose of this project was to determine the cell origins and to investigate the histochemical properties of the products present in adenomatoid odontogenic tumor (AOT). In 1992, the World Health Organization (WHO) categorized AOT as a mixed, epithelial and mesenchymal, odontogenic tumor. But in the 2005 edition of the WHO classification, it was reclassified as an epithelial-only tumor. There was no reason provided about this reclassification in the 2005 edition of the WHO classification. Therefore, whether AOT should be classified as a mixed or an epithelial-only tumor remains controversial. In the present investigation, immunohistochemical studies with nestin, dentin sialophosphoprotein (DSPP), cytokeratin, and vimentin were performed in 21 AOT cases and analyzed according to the various cells structures and arrangements seen in AOT. The results showed that 20/21 (95.23%) cases demonstrated nestin expression, 0/21 (0%) cases demonstrated DSPP expression, 21/21 (100%) cases demonstrated cytokeratin expression, and 20/21 (95.23%) cases demonstrated vimentin expression. Cells of the anastomosing cords, intermediate cells, and cells that formed some of the rosette/duct-like structures showed co-expression of vimentin and cytokeratin. In some cases, the cells that constituted the rosette structures showed overlapping expression of nestin, cytokeratin, and vimentin. Histochemical staining with Sirius red demonstrated the presence of collagen types I and III, which are mesenchymal cell products, in some of the tumor products. These results suggest that there is a mixed population of both epithelial and mesenchymal cells present in AOT. We conclude that AOT is a mixed odontogenic tumor with some products that are secreted by mesenchymal cells. The results of this project provide evidence for the proper classification of AOT. | en |
