Adenomatoid odontogenic tumor mimicking a periapical (radicular) cyst: a case report.

The adenomatoid odontogenic tumor (AOT) is a benign (hamartomatous), noninvasive lesion with slow but progressive growth. A rare subvariant of the extrafollicular type of AOT may mimic periapical disease radiographically. We report on a 15-year-old girl with a periapical radiolucent lesion affecting teeth 7 and 8 initially suspicious of periapical disease, although clinical findings seemed to indicate a nonendodontic lesion. An exploratory surgical approach was chosen, and the final diagnosis of the removed noncystic tissue mass was microscopically confirmed to be an AOT.