Odontogenic Tumors Flashcards
Odontogenic Tumors: 3 Tissue categories of origin
- Odontogenic Epithelium
- Mesenchymal
- Mixed
Tumors of Odontogenic Epithelium
- Ameloblastoma
- Adenomatoid odontogenic tumor
- Calcifying epithelial odontogenic tumor
- Squamous odontogenic tumor
Ameloblastoma types
- Multicystic (solid conventional) – 86%
- Unicystic – 13%
- Peripheral – 1%
Ameloblastoma stats
• Usually 3rd to 7th decades, no gender predilection
• 85% mandible (molar/ramus most common), 15% maxilla
(usually posterior)
Ameloblastoma - Radiographic
• Multilocular radiolucency usually; soap bubble (large loculations),
honeycomb (small loculations)
• Buccal and lingual cortical expansion
• Often associated with an unerupted tooth (3rd molar)
• Margins may show irregular scalloping
Ameloblastoma and roots
Resorption of
adjacent tooth
roots is
common
Ameloblastoma – Treatment and Prognosis
• Enucleation and curettage (recurrence 50% to 90%)
• Marginal resection (recurrence up to 15%)
• En bloc resection, with at least 1 cm clear margins (highest cure rate)
• Radiation therapy not recommended, except to control nonresectable
tumors.
Desmoplastic Ameloblastoma
• The exception to the rules for conventional
ameloblastoma
– One of several histologic subtypes of ameloblastoma
– Preference for anterior jaws, most often maxilla
– Radiographically resembles a fibro-osseous lesion
– Mixed radiolucent/radiopaque appearance due to osseous
metaplasia within dense fibrous septa
– Varying opinions regarding aggressiveness of tumor and
recommended treatment
Unicystic Ameloblastoma
• 50% diagnosed during the second decade of life
• Over 90% are found in the mandible, usually posterior
• Circumscribed radiolucency, often surrounding the crown of an
unerupted third molar, similar to dentigerous cyst
Unicystic Ameloblastoma Dx guidlines
To be diagnosed as unicystic, the
ameloblastoma must be unicystic grossly,
radiographically, and histologically
Unicystic Ameloblastoma – Treatment and
Prognosis
• Enucleation is most common, although if the tumor is found to be
mural (satellites of ameloblastic epithelium within wall of cyst),
further treatment is indicated
• 10% to 20% recurrence after enucleation
Peripheral Ameloblastoma
• 1% of ameloblastomas
• GUM BUMP - Painless, non-ulcerated, sessile or pedunculated lesion
on gingiva or alveolar mucosa; usually posterior, more common in
mandible
• Average age 52
• Innocuous behavior. Local surgical excision recommended, with 15%
to 20% recurrence initially; second recurrence is rare.
• Rule out central ameloblastoma
Gum Bump Differential
Pyogenic granuloma Fibroma Ossifying fibroma Peripheral giant cell granuloma Parulis Others: Peripheral odontogenic fibroma, peripheral ameloblastoma
Malignant Ameloblastoma
• Less than 1% of all ameloblastomas
• Metastasis, with secondary tumors exhibiting histology similar to
primary tumor (benign cytology under the microscope)
• Mets to lungs most common… aspiration or implant mets. Metastasis
may also occur via blood or lymphatic channels
• Poor prognosis
Ameloblastic Carcinoma
• Cytologic features of malignancy either in primary or secondary
tumors (microscopically ugly)
• More aggressive, with ill-defined margins, destruction of cortex, and
extension into soft tissue
• Poor prognosis
Adenomatoid Odontogenic Tumor (AOT)
• 3%-7% of odontogenic tumors
• “Two thirds tumor”: Female, young (ages 10 to 19), anterior jaws,
maxillary, associated with impacted tooth, radiopacities
• Most often asymptomatic, less than 3 cm. May cause painless bony
expansion if large
Adenomatoid
Odontogenic Tumor
2/3’s tumor: Female Anterior Maxillary Young Canine tooth
