The ultrastructure of the adenomatoid odontogenic tumor

An adenomatoid odontogenic tumor (AOT) which occurred in the maxilla of an 8-year-old boy was studied by the light and electron microscopy. The tumor was found to contain cells resembling preameloblasts, the stratum intermedium, and the stellate reticulum, suggesting its origin from the enamel organ, in agreement with previous reports. Characteristic ductlike structures are thought to be formed as a result of secretory activity of the tumor cells, rather than degeneration. Duct-lining cells ultrastructurally similar to preameloblasts were found to contain electron-dense granules. These granules are believed to play a role in secretion by tumor cells, a concept not previously considered. The results of previous ultrastructural studies of the AOT are reviewed and summarized.