A case of adenomatoid odontogenic tumor

1) A 31-year-old woman with adenomatoid odontogenic tumor of the frontal teeth in the maxilla was examined histochemically and electron microscopically with reference to the literature.2) Histologically, a large cystic cavity was formed, and in a portion of the stratified squamous epithelium lining the inner surface of the cavity, a tumor mass showing typical tissue structure of adenomatoid odontogenic tumor was found.3) Histochemically, acidophilic materials with calcification within the tumor nest showed positive amyloid staining (Congo red staining, green birefringence), and the area of cord like proliferation was alkaline-phosphatase positive.4) Electron microscopically, solid cell layers consisted of polygonal cells similar to the inner enamel epithelium, and aggregates of fine granular fibers similar to amyloid were observed between these cells. Moreover, the stratified epithelium in the inner surface of the cyst consisted of squamous epithelium, resembling dentigerous cysts.