Odontogenic Tumours Flashcards
What is the prevalence of odontogenic tumours in the UK?
1% of oral&maxfax lesions sent for histopathological assessment in uk
What is the ratio of benign > malignant odontogenic tumours?
100:1
How do odontogenic tumours tend to present?
- asymptomatic
- non eruption of teeth
- late stage bone expansion
- pain usually secondary to infection or pathological fracture of bone
How are odontogenic tumours sometimes found?
Incidental finding when imaging for other dental reasons
What determines the classification of odontogenic tumours? What are the classification groups?
Based on tissue of origin
- epithelial
- mesenchymal
- mixed [epithelium and mesenchyme]
What odontogenic tumour classification can have dentine/enamel formation?
MIXED
- concept of induction
- dentine is formed from mesenchymal cells
What does induction mean in reference to enamel and dentine?
You cannot have enamel until dentine has been deposited
What are some odontogenic tumours sources of epithelium?
SAME AS ODONTOGENIC CYSTS
- Rests of Malassez
- Rests/glands of Serres
- Reduced enamel epithelium
What is the function of the dental lamina?
Formation of tooth germs
What are examples of odontogenic tumours from the epithelial classification?
- ameloblastoma
- adenomatoid odontogenic tumour
- calcifying epithelial odontogenic tumour
What are examples of odontogenic tumours from the mesenchymal classification?
odontogenic myxoma
What are examples of odontogenic tumours from the mixed classification?
odontoma
What do odontogenic tumours usually tend to be?
> 50% are either ameloblastoma or odontoma
What is an ameloblastoma?
Benign epithelial tumour
- locally destructive but slow growing
- typically painless
What is the incidence of Ameloblastomas?
- 1% of oral & maxillofacial tumours
- most common in 4-6th decade
- 80% occur in posterior mandible
- M > F
Where do Ameloblastoma tumours tend to be located?
Posterior mandible (80%)
What type of tumour is seen radiographically here?
Ameloblastoma
What are the different types of Ameloblastomas based on the radiographic classification?
- multicystic [80-90%]
- unicystic
What are the different types of Ameloblastomas based on the histological classification?
- follicular
- plexiform
- desmoplastic
How do ameloblastomas present radiographically?
- well defined corticated margins
- potentially scalloped margins
- ‘Knife edge’ external root resorption of adjacent teeth
- ‘soap bubble’ appearance in multicystic types
- primarily radiolucent
- displacement of adjacent structures
- cause thinning of bony cortices
How does the histology of follicular ameleblastomas present?
Islands present in a fibrous tissue background
How does the histology of plexiform ameleblastomas present?
Why can ameloblastomas grow & infiltrate into the jaw bone?
No connective tissue capsule
- leads to high recurrence rate
How are ameloblastomas managed?
Surgical resection with margin
- due to recurrence being common
What % of ameloblastoma cases tend to recur after surgical removal?
up to 15%
Why should ameloblastomas be surgically resected?
- risk of malignant change (<1% of cases)
What are adenomatoid odontogenic tumours?
Benign epithelial tumours
How do adenomatoid odontogenic tumours classically present?
Unilocular radiolucency with internal calcifications around crown of unerupted maxillary canine
What is the incidence of adenomatoid odontogenic tumours?
- 3% of odontogenic tumours
- most common in 2nd decade
- F > M
- majority occur in anterior maxilla
Where in the mouth are you most likely to find an adenomatoid odontogenic tumours?
Anterior maxilla
What do adenomatoid odontogenic tumours tend to be associated with?
Unerupted tooth
- commonly maxillary canines
What is the difference between AOTs and dentigerous cysts?
AOTs attached apical to cemento-enamel junction VS dentigerous cysts attached AT cemento-enamel junction
How do adenomatoid odontogenic tumours present radiographically?
- unilocular radiolucency
- internal calcifications/radiopacities
- well defined & corticated margins
- may displace adjacent structures BUT external root resorption rare
What is seen here on this radiograph?
Adenomatoid odontogenic tumour
How does the histology of AOTs present?
What is a calcifying epithelial odontogenic tumour?
Benign epithelial tumour
- 1% of odontogenic tumours
Where are calcifying epithelial odontogenic tumours located typically?
Posterior mandible most common site
What is seen on this OPT radiograph?
Calcifying epithelial odontogenic tumour
How do calcifying epithelial odontogenic tumours present?
- slow growing but can become very large
- half are associated with an unerupted tooth
- radiolucency often with internal radiopacities
- variable radiographic presentation otherwise
What pathology is seen on this radiograph?
CEOT (calcifying epithelial odontogenic tumour)
What is an odontogenic myxoma?
Benign mesenchymal tumour
- 3-6% of odontogenic tumours (second most common tumour after ameloblastoma)
- mandible > maxilla
What pathology is seen on this radiograph?
Odontogenic myxoma
How do odontogenic myxoma’s present radiographically?
- well defined radiolucency ± thin corticated margin
- smaller lesions unilocular
- larger lesions multilocular with scalloped margins [soap bubble appearance]
- larger lesions may cause displacement
- external root resorption rare
How do odontogenic myxoma’s present histologically?
- loose myxoid tissue with stellate cells
- islands of inactive odontogenic epithelium
- no capsule –> locally invasive
How are odontogenic myxoma’s managed?
- curettage or resection [depending on size]
- MUST FOLLOW UP = high recurrence rate: 25%
What are odontomas?
Benign mixed “tumour”
- technically a hamartoma
- malformation of dental tissue
- made up of enamel, dentine, cementum & pulp
How do odontomas present similarly to teeth?
- surrounded by dental follicle
- made up of enamel, dentine, cementum & pulp
Where are odontomas usually located?
lie above inferior alveolar canal
What pathology is seen in this radiograph?
odontoma
What are the different types of odontomas?
- Compound odontoma [ordered dental structures]
- Complex odontoma [disorganised mass of dental tissues]H
How are compound odontomas described? Where are they typically located?
- multiple mini teeth
- “denticles”
- more common in anterior maxilla
How are complex odontomas described? Where are they typically located?
- disorganised mass of dental tissues
- more common in posterior body of mandible
What type of odontoma is more common?
Compound > complex (2:1)
