18. Odontogenic tumours Flashcards
(55 cards)
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
