a benign epithelial odontogenic tumor appearing radiographically as a well-circumscribed, radiolucent-radiopaque lesion usually surrounding the crown of an impacted tooth in an adolescent or young adult; characterized histologically by columnar cells organized in a ductlike configuration interspersed with spindle-shaped cells and an amyloidlike deposition that gradually undergoes dystrophic calcification. SYN: adenoameloblastoma, ameloblastic adenomatoid tumor.