8 - Odontogenic tumours Flashcards
What is the split of benign vs malignant odontogenic tumours?
100:1 benign:malignant
How are odontogenic tumours classified?
- based on origin of tissue
- epithelial
- mesenchymal
- mixed
What type of tumour can have enamel and dentine formation?
- mixed
- due concept of induction
- dentine is mesenchymal and enamel is epithelial, but dentine induces enamel production
Give examples of epithelial odontogenic tumours.
- ameloblastoma
- adenomatoid odontogenic tumour
- calcifying epithelial odontogenic tumour
Give examples of mesenchymal odontogenic tumours.
Odontogenic myxoma
Give examples of mixed odontogenic tumours.
Odontoma
What is an ameloblastoma?
- benign epithelial tumour
- locally destructive but slow growing
- painless
- high recurrence
What is the incidence of ameloblastoma?
- 30-50 years
- 80% in posterior mandible
- M>F
What are the radiological types of ameloblastoma?
- multicystic
- unicystic (younger patients, less recurrence)
What are the histological types of ameloblastoma?
- follicular (most common)
- plexiform
- desmoplastic
Describe the radiographic appearance of ameloblastoma.
- well defined, corticated margins
- multicystic are scalloped
- multicystic can have thick septae, giving “soap bubble” appearance
- primarily radiolucent
- can cause displacement of adjacent structures, thinning of bony cortices and knife edge root resorption
What is the management of ameloblastoma?
Surgical resection with margin
What is the risk of malignant transformation of ameloblastoma?
<1%
What is the risk of recurrence of ameloblastoma?
15%
What is adenomatoid odontogenic tumour (AOT)?
- benign epithelial tumour
- 75% associated with unerupted tooth
- impedes eruption of associated tooth
What is the incidence of AOT?
- teenagers
- F>M
- majority in anterior maxilla
Describe the radiographic appearance of AOT.
- unilocular radiolucency with internal calcifications/radiopacities
- well defined, corticated/sclerotic margins that attach apical to CEJ (join PDL)
- may displace adjacent structures but root resorption rare
Describe the histology of AOT.
- distinctive with patchy calcification
- fibrous tissue capsule
- duct like structures
Describe the histology of follicular ameloblastoma.
- islands in fibrous tissue
- cystic changes
- ameloblast like cells
- stellate reticulum like tissue
Describe the histology of plexiform ameloblastoma.
- ameloblast like cells back to back
- stellate reticulum like tissue
- fibrous tissue
What is CEOT?
- calcifying epithelial odontogenic tumour
- benign epithelial tumour
- aka Pindborg tumour
- slow growing but can become large
- 50% associated with unerupted tooth
What is the incidence of CEOT?
- 40s
- M>F
- posterior mandible is most common site
Describe the radiographic appearance of CEOT.
- radiolucency with internal radiopacities
- calcifications of varying sizes
- variable radiographic appearance otherwise
What is an odontogenic myxoma?
- benign mesenchymal tumour
- slow growth along bone before causing notable bucco-lingual expansion
- locally invasive, high recurrence and difficult to remove
