odontogenic neoplasms Flashcards
what is ameloblastoma?
benign but locally aggressive neoplasm of odontogenic epithelial origin
what does ameloblastoma looks like microscopically?
cells resemble the ameloblasts of the enamel organ, but no enamel is produced
what are the characteristics of ameloblastoma?
while considered the most common odontogenic neoplasm, it only constitutes about 0.2% of oral pathology biopsy cases
no sex predilection
wide age range, from 3rd to 7th decades
most (80-85%) occur in the mandible, usually the molar ramus region
about 20% are associated with an impacted tooth
lesion grows slowly, destroying tissue, but usually expanding rather than perforating bone
typically asymptomatic except for swelling
what does ameloblastoma look like radiographically?
a small lesion usually presents as a unilocular radiolucency with well-defined borders
as the lesion progresses, the classic multilocular expansile radiolucency frequently develops
what is the ameloblastoma desmoplastic variant?
described initially in 1984
distinctive radiologically as well as histologically
radiographs usually show a poorly demarcated radiolucency with numerous radiopaque flecks
similar in appearance to benign fibro-osseous lesion
what does ameloblastoma look like histologically?
several different patterns, follicular and plexiform are most common
small tumor islands which show cuboidal or columnar cells at their periphery
the center of the tumor islands is composed of loosely arranged polyhedral epithelial cells that resemble stellate reticulum
what is the treatment of ameloblastoma?
depends on size and site of the lesion
small lesion- aggressive currettage or small en bloc resection
large lesion- large enbloc resection or maginal segmental resection with reconstruction
what is the prognosis of ameloblastoma?
guarded
with simple curettage, recurrence rates reported to be 50-90%
even with marginal resection, recurrence rates up to 15%
maxillary lesions warrant more aggressive surgical removal due to their anatomic location
what is peripheral ameloblastoma?
clinically present as an asymptomatic gingival mass in a middle aged adult, usually mandible
typically less than 2 cm in diameter
important to note that this is an innocuous lesion that can easily be cured by local excision, little tendency to recur
what is calcifying epithelial odontogenic tumor?
CEOT, pindborg tumor
rare odontogenic epithelial neoplasm initially described by Pindborg in 1956
what is the histogenesis of the calcifying epithelial odontogenic tumor?
thought to be derived from cells of stratum intermedium
what are the characteristics of calcifying epithelial odontogenic tumor?
mean age at diagnosis- 40 years with no sex predilection
most arise in the posterior mandible
asymptomatic, swelling may be noted
50% associated with an impacted tooth
what is the radiographic characteristics of calcifying epithelial odontogenic tumor?
diffuse or well circumscribed radiolucency unilocular when small
with growth, lesion may become multilocular
radiopaque flecks often develop as lesion enlarges
what does calcifying epithelial odontogenic tumor look like histologically?
sheets or strands of polyhedral epithelial cells with eosinophilic cytoplasm
the nuclei are frequently pleomorphic, but mitoses are rare
epithelial cells may be associated with variable amounts of eosinophilic, acellular material that stain as amyloid
calcifications develop in this unique amyloid material, forming lamellated structures called liesegang rings
what is the treatment and prognosis of calcifying epithelial odontogenic tumor?
conservative excision with peripheral ostectomy
prognosis- 15% recurrence rate
what are the characteristics of adenomatoid odontogenic tumor?
usually arises in a younger patient, mean age- 18 years, with 75% under 20 years of age
2:1 female predilection
2:1 maxillary predilection
75% of these lesions develop in the anterior jaws
75% are associated with an impacted tooth
rarely, extraosseous lesions have been reported
other than possible swelling, these tumors are asymptomatic
what does adenomatoid odontogenic tumor look like radiographically?
well-circumscribed unilocular radiolucency that may contain radiopaque flecks
separation of roots or displacement of adjacent teeth occurs frequently
when associated with an impacted tooth, the lesion often extends apically beyond cemental enamel junction
this feature may help distinguish AOT radiographically from dentigerous cyst
what does adenomatoid odontogenic tumor look like histologically?
well encapsulated lesion
the tumor cells form swirling spindle cell nests with duct like structures of varying sizes
foci of basophilic calcified material may also be seen
what is the treatment and prognosis of adenomatoi odontogenic tumor?
tx- enucleation
prognosis- excellent
recurrence is very rare
what are the characteristics of ameloblastic fibroma?
diagnosed most frequently in younger patients, typically during the first two decades of life
posterior mandible is the most common site (70% of all cases)
small lesions are asymptomatic, while larger ones produce painless swelling
what are the radiographic characteristics of ameloblastic fibroma?
unilocular when small
larger lesions can become multilocular
margins tend to be well-defined
what are the histologic characteristics of ameloblastic fibroma?
myxoid connective tissue that resembles dental papilla that contains strands and islands of odontogenic epithelium that resembles dental lamina
the epithelial component occasionally resembles ameloblastoma
connective tissue resembles dental papilla
admixed with strands and islands of odontogenic epithelium that resembles dental lamina
epithelial islands can resemble follicular or plexiform ameloblastoma
what is the treatment and prognosis of ameloblastic fibroma?
treatment consists of aggressive curettage
prognosis- good
recurrence rate is low (0-18%)
rare malignant transformation
what are the characteristics of ameloblastic fibro-odontoma?
odontogenic tumor with features of ameloblastic fibroma as well as odontoma
usually diagnosed in children, average age of 10 years
asymptomatic swelling with large lesions
failure of tooth eruption may be noted
equal frequency in mandible and maxilla
