= ADAMANTINOMA OF JAW

= benign locally aggressive infiltrative epithelial neoplasm

Prevalence: most common (10%) of odontogenic tumors

Origin: enamel-forming odontogenic epithelium of dental follicle that failed to regress during embryonic development; 30–50% arise from epithelium of dentigerous cyst (= mural ameloblastoma)

Classification (WHO 2006):

1. intraosseous: arises in jaw as unicystic / desmoplastic / mixed cystic + solid (most aggressive) lesion
2. extraosseous (peripheral): sessile / pedunculated mass confined to gingiva / alveolar mucosa

Age: 20–40 years; M÷F = 1÷1

• slow-growing painless mass

Location: ramus + posterior body of mandible (75%), maxilla (25%)

Site: in region of bicuspids + molars, typically 3^rd molar (angle of mandible commonly affected)

• well-defined well-corticated unilocular lucent lesion (DDx: odontogenic keratocyst, dentigerous cyst)
• uni- / multilocular lesion with internal septations (honeycomb / soap bubble appearance)
• typically expansile with scalloped margin
• may perforate lingual cortex + infiltrate adjacent soft tissues
• erosion of roots of adjacent teeth (UNIQUE)
• often associated with crown of an impacted / unerupted tooth

CT:

• cystic areas of low attenuation + isoattenuating enhancing solid component
• ± resorption of roots of adjacent teeth

Prognosis: frequently local recurrence even more aggressive after excision; rarely metastasize to lung

Cx: may undergo carcinomatous change

Rx: wide surgical resection ± radiation therapy