BDS4 odontogenic tumours Flashcards
What are the 3 groups of odontogenic tumours?
Epithelial
Mesenchymal
Mixed - epithelial and mesenchyme
What is the first dental hard tissue to form?
Dentine - formed by odontoblasts
Mesenchymal in origin
What is the concept of induction?
Only MIXED tumours can have dentine/ enamel formation
Presence of dentine is important for induction of maturation of ameloblasts and formation of enamel.
Where are odontogenic tumours most likely to occur?
Most likely to occur in the jaw bones but some rare cases can occur in soft tissue
How are odontogenic tumours often discovered?
Often incidental finding due to imaging to other reasons
Non-eruption of teeth
Late-stage bony expansion
What % of oral/ maxillofacial lesions that are sent for histopathological assessment in the UK are odontogenic tumours?
1% - rare
What are the most common odontogenic tumours of epithelial origin?
Ameloblastoma
Adenomatoid odontogenic tumour (AOT)
Calcifying epithelial odontogenic tumour
What is a common type of odontogenic tumour of mesenchymal origin?
Odontogenic myxoma
What is a common type of odontogenic tumour of mixed origin?
Odontoma/ odontome
What are the characteristics of an ameloblastoma?
Benign epithelial tumour
Locally destructive but slow-growing
Typically painless
Most common in 4-6th decades
80% occur in posterior mandible
Characteristic pattern of growth - extends in every direction fairly equally.
What are the 2 radiological appearances of an ameloblastoma?
Multi-cystic - 85-90% - typically more common in older patients
Uni-cystic - typically more common in YOUNGER patients
What are the margins generally like in an ameloblastoma?
Well-defined, corticated
Potentially scalloped
What are the effects an ameloblastoma can have on adjacent structures?
Displacement of adjacent structures - can push other structures out of the way e.g. teeth
Thinning of bony cortices
Knife-edge external root resorption - clean cut roots - not ragged like other lesions may be
What is the management of an ameloblastoma?
Surgical resection with margin
What is the most common radiographic presentation of an adenomatoid odontogenic tumour (AOT)?
Benign epithelial tumour
Uni-locular radiolucency with internal calcification around crown of unerupted maxillary canine
Margins well-defined & corticated/ sclerotic
What is the common histology of AOT?
Distinctive with patchy calcification
Duct-like structure
What is the common histology of ameloblastoma?
Ameloblast-like cells
Stellate reticulum like tissue
Fibrous tissue
What is very characteristic of adenomatoid odontogenic tumour (AOT)?
Typically attached apical to ECJ - asymmetrical involvement of root and crown of the tooth
Presentation of a calcifying epithelial odontogenic tumour (CEOT)?
Slow-growing but can become large
Half are associated with and unerupted tooth
Variable radiographic presentation
Radiographic presentation of odontogenic myxoma?
Well-defined radiolucency
Soap-bubble appearance common for larger lesions
Smaller lesions unilocular
Slow growth along bone before causing notable bucco-lingual expansion
Histological presentation of odontogenic myxoma?
Loose myxoid tissue with stellate cells
May contain islands of inactive odontogenic epithelium
Management of odontogenic myxoma?
Curettage - scraped out
Resection - removal of bone and tumour
Depends on size
Why is follow-up of treated odontogenic myxoma important?
High recurrence rate - 25%
Describe an odontoma?
Benign mixed tumour
Malformation of dental tissue
Lie above inferior alveolar canal - similar to teeth
Surrounded by a dental follicle
What are the 2 types of odontoma and describe each?
Compound odontoma - ordered dental structures - may appear as multiple “mini teeth” e.g. denticles
More common in anterior maxilla
Complex odontoma - disorganised mass of dental tissues
More common in posterior body of mandible
