Unsuspected small ameloblastoma in the alveolar bone: a collaborative study of 14 cases with discussion of their cellular sources

Abstract

Background: Intraosseous ameloblastoma (IA) is the quintessence of epithelial odontogenic tumor and histologically and behaviorally defined as an undoubted neoplastic process. Current information must lead to the consensus that IA arises from the embryologic inclusions of odontogenic epithelium within the jawbone. Nevertheless, clinically oriented evidence is limited to this day.

Methods: The clinical and radiographic features, behavior, and pathology of 14 cases of small IA confined to the alveolar region were systematically examined.

Results: Six cases were a chance finding. There was no gender predilection and half of the lesions clustered in middle age (>40 years). The posterior region of the mandible (n = 7) and the anterior segment of the maxilla (n = 4) were favored. Five radiographic characteristics were recognized: interradicular (n = 5) and periradicular (n = 3), and periapical, residual and pericoronal (n = 2 each). They showed solid (n = 12) or unicystic (n = 2) growth pattern and 12 lesions were divided into seven follicular, three desmoplastic, and two plexiform subtypes. The main location of tumor was microscopically traceable in six cases; three interradicular type outside the periodontal ligament space and two periradicular and one periapical variants inside.

Conclusion: By in-depth evaluation of the spatial relationship between tumor and its surrounding structure, the alveolar process, periodontal ligament space, and pericoronal area are all the likely starting points of IA. This report re-awakens the oral pathologist to the histogenetic significance of incipient IA as the only available human specimen for reappraisal of their origin.