18. Odontogenic tumours Flashcards
What is the inductive theory?
- Pre-ameloblasts induce dental papilla
- Dental papilla differentiates pre-odontoblasts
- Odontoblasts produce dentine
- Dentine induces pre-ameloblast maturation
- Ameloblast produce enamel
How would you describe what an ameloblastoma is?
Benign but locally invasive neoplasm consisting of proliferating odontogenic epithelium in a fibrous stroma/
Which people is ameloblastoma seen most in?
Africans and African Americans
40-50 year olds
Where is ameloblastoma commonly found?
80% mandible
70% molar
What is the radiograph finding of ameloblastoma?
Multiocular radiolucency
Root resorption
Might mimic a dentigerous cyst
What is the symptoms of ameloblastoma?
Slow growing
Facial deformation
May be asymptomatic
Cortical perforation is a late finding
What is the recurrence of ameloblastoma?
High= 70-90%
What is ameloblastoma derived from?
Though to be from dental lamina residues
Describe histology of follicular ameloblastoma?
Discrete islands of epithelium
Varying amounts of fibrous stroma
Cyst formation in epithelial islands
Central angular cells- stellate reticulum
Peripheral columnar cuboidal cells with reverse nuclear polarity- preameloblasts
Describe histology of plexiform ameloblastoma?
Centrally stellate reticulum cells with peripheral preameloblasts
Cyst formation is due to stromal degeneration
What are the ameloblastoma variants?
Follicular- discrete islands of epithelium, epithelial cysts common
Plexiform- irregular masses or network strands, stromal cysts common
Acanthomatous- squamous metaplasia
Basal cell- like basal cell adenocarcinoma
Granular- cuboidal, columnar rounded cells with acidophilic granules
What age is a unicystic ameloblastoma found in?
Younger age- 20 to 30
What is the radiograph for unicystic ameloblastoma?
Well defined, unilocular- looks like dentigerous cyst
What are the 3 types of unicystic ameloblastoma?
Luminal- cyst has ameloblastoma tissue lining
Intraluminal- proliferation of intraluminal nodules
Mural- ameloblastoma nests deep in the cystic wall
What is the treatment for unicystic ameloblastoma?
Enucleation of luminal and intraluminal
Resection of mural
What is peripheral ameloblastoma?
Thought to derive from extraosseous dental lamina rests and basal cells
Seem to be not as invasive as intraosseous types
What are the symptoms of calcifying epithelial odontogenic tumour?
Rare, benign, locally invasive but less than ameloblastomas
Where is calcifying epithelial odontogenic tumour found?
Mandible molar premolar area
50% associated with crown of unerupted tooth
What is the radiograph for calcifying epithelial odontogenic tumour?
Irregular radiolucent and radiopaque bodies
What is the histology of calcifying epithelial odontogenic tumour?
Polyhedral cells with eosinophilic cytoplasm
Amyloid like material which can calcify
Fibrous stroma
Liesegang rings- concentric calcifications, diffusion, chemical reaction, precipitation
Where is an adenomatoid odontogenic tumour found?
20-30
Anterior maxilla
Can be associated to unerupted teeth
What is the radiograph for adnomatoid odontogenic tumour?
Radiolucent
Can have faint radiopacities
Might stimulate dentigerous cyst
What is the histology of adenomatoid odontogenic tumour?
Sheets, strands, whorled masses of columnar ameloblast like cells
Forming duct like structures
With eosinophilic material centres- maybe containing malformed dental organ. Origin- stratum intermedium
May contain dysplastic dentine and enamel matrix
Where is a primordial odontogenic tumour found?
Very young, posterior
What is the x ray for primordial odontogenic tumour?
Well defined radiolucency associated with unerupted teeth
What is the histology of primordial odontogenic tumour?
Mesenchymal mass covered by odontogenic epithelium
Most likely an abortive tooth germ that has failed to develop
Whee is ameloblastic fibroma found?
Molar premolar region
What are the characteristics of ameloblastic fibroma?
Rare over the age of 21
Radical resection unnecessary
Low recurrence
Well circumscribed
Rare
Benign
What is the x ray finding of ameloblastic fibroma?
Unilocular
Might mimic a dentigerous cyst or be associated with unerupted tooth
What is the histology of ameloblastic fibroma?
Contains both epithelial and mesenchymal neoplastic components
Odontogenic epithelium in strands
Stellate reticulum less adundant
Highly cellular fibroblastic tissue resembling the dental papilla
Hyaline tissue bordering the epithelium
What is ameloblastic fibrodentinoma?
Ameloblastic fibroma and dentine
Cellular dentine, dentine is poorly formed
What is ameloblastic fibro-odontoma?
Ameloblastic fibroma and enamel and dentine
Hamartoma
Difficult to differentiate from complex odontome
What is odontoameloblastoma?
Very rare
Ameloblast like epithelium with enamel and dentine
What is an odontome and its lining?
Hamartoma
Encapsulated
What is a compound odontome?
Made of small denticles or malformed teeth from overactivity of the dental lamina
Found in anterior maxilla
What is a complex odontome?
All dental tissues well formed but they are disorderly arranged.
Molar/premolar area
Where is a calcifying cystic odontogenic tumour found?
Anterior to first molar
75% intraosseous
What does a calcifying cystic odontogenic tumour look like?
Dentinogenic ghost cell tumour is similar, but it is solid and true neoplasm
What is the x ray of calcifying cystic odontogenic tumour?
Uni or multilocular
Plus radiopaque material
Can be associated to unerupted tooth crown
What is the histology of calcifying cystic odontogenic tumour?
Cyst lined by epithelium with basal layer of ameloblast like cells
Overlying stellate like reticulum
Ghost cells which may calcify
What tumours are derived from just mesenchymal tissue?
Odontogenic fibroma
Myxoma
Myxofibroma
Where can a fibroma be found?
In place of a missing tooth
Or in relation to crown or root of unerupted tooth
What is the histology of odontogenic fibroma?
Fibroblastic neoplasm containing varying amounts of inactive odontogenic epithelium
Fibrous tissue more mature than AF
Contains dentinoid
Cementoid may be present
What does a peripheral case of odontogenic fibroma look like clinically?
Fibrous epulis
What is an odontogenic myxoma?
Rare but locally aggressive
What is the x ray for odontogenic myxoma?
Multilocular radiolucency- soap bubble appearance
What is the histology for odontogenic myxoma?
Non encapsulated
Stellate fibroblasts
Abundant connective tissue ground substance-glycosaminoglycans
Sometimes odontogenic epithelium
Where is cementoblastoma found?
Under 25 years
Associated with roots of tooth, otherwise osteoblastoma
Mandible premolar molar areaa
What is the x ray for cementoblastoma?
Well demarcated mottled dense radiopaque
Attached to root
Root resorption
Surrounded by thin radiolucent line
What is the histology of cementoblastoma?
Mass of calcified cementum like material
Cells in lacunae
Cementicle like cells
Mass uncalcified at periphery
Cementoclasts
May recur if not removed completely
What comes under cemento osseous dysplasia?
Periapical cemental dysplasia
Florid cemento osseous dysplasia
Where is periapical cemental dysplasia found?
Anterior maxilla
Vital teeth
Afrocarirbean adult women
What is the histology of periapical cemental dysplasia?
Fibroblastic first then patches of sclerotic bone- cementifying fibroma
What is florid-cemento osseous dyslasia found?
Middle aged black females
Bilateral and symmetrical
What is the histology of florid cemento osseous dysplasia?
Diffuse radiopaque masses of basophilic acellular cementum
No radiolucent border
