Odontogenic Tumours Flashcards
Are odontogenic tumours mainly benign or malignant?
Mostly benign
What are the symptoms of an odontogenic tumour?
Mainly asymptomatic - incidental finding
Pain is usually secondary to infection or pathological fracture
What are the 3 main types of odontogenic tumours?
Epithelial
Mesenchymal
Mixed
Which type of odontogenic tumours have enamel/ dentine formation present? Why?
Mixed tumours (epithelial and mesenchyme)
Due to the concept of induction:
- odontoblasts are mesenchymal- dentine induces the maturation of ameloblasts to form enamel
Cannot have enamel without dentine
What are the 3 main sources of epithelium?
Rests of molasses (hertwigs root sheath)
Rests of serres (dental lamina)
Reduced enamel epithelium (enamel organ)
What is an example of an epithelial odontogenic tumour?
Ameloblastoma
What is an example of a mesenchymal odontogenic tumour?
Odontogenic myxoma
What is an example of a mixed odontogenic tumour?
Odontoma
What are the 2 most common odontogenic tumours?
Ameloblastoma
Odontoma
What is an Ameloblastoma?
Epithelial odontogenic tumour
Locally destructive, slow growing
Most common in posterior mandible
What is the Radiographic appearance of Ameloblastoma?
Multi cystic (most common) - may have thick curved septae
(Uni cystic in younger patients)
Well defined corticosteroid margins
Displacement of adjacent structures, thinning of bony cortices
Knife edge external root resorption
What is a clinical characteristic finding of Ameloblastoma?
Expands in all directions
Hard bony swelling
Teeth not TTP
What are the histological features of Ameloblastoma?
Follicular - islands of fibrous tissue
Plexiform - Ameloblastoma cells arranged in strands, no connective tissue capsule
Desmoplastic
What is the management of Ameloblastoma?
Surgical resection with margin (1cm normal tissue)
What is the recurrence rate of Ameloblastoma?
15%
What is the malignant transformation of Ameloblastoma?
Very rare <1% cases
- ameloblastic carcinoma
What is an adenomatoid odontogenic tumour (AOT)?
Benign epithelial tumour
Unilocular radiolucnecy with internal calcifications around the crown of unerupted maxillary canines. Often not symmetrical.
Causes impeded eruption
- anterior maxillary (Ameloblastoma= posterior mandible)
- spreads past CEJ
What is the histological findings of AOT?
Distinctive patchy calcifications
Duct like structure
Well developed fibrous capsule surrounding cells - tumour removal is simple and recurrence is low
What is calcifying epithelial odontogenic tumour (CEOT)?
Occurs most commonly in posterior mandible
50% associated with unerupted tooth
Radiolucency with internal radiopacities
- very variable presentation
What is an odontogenic myxoma?
A benign mesenchymal tumour
Most common in mandible
Slow growing along bone before causing notable bucco lingual expansion
What is the Radiographic presentation of an odontogenic myxoma?
Well defined radiolucency with thin corticated margins
Small lesions= unilocular
Large lesions= multilocular with scalloped margins (soap bubbles)
What is the histological findings of an odontogenic myxoma?
Loose myxoid tissue with stellate cells
No capsule - locally invasive
What is the management of odontogenic myxoma?
Curettage or resection (depending on size)
High recurrence rate (25%) so follow up.
What is an Odontoma?
A benign mixed tumour
- malformation of dental tissue
- mature to a certain stage, can be associated with dentigerous cysts
- surrounded by dental follicle
Lie ABOVE inferior alveolar canal
What are the 2 types of Odontoma?
Compound - appear as mini teeth (denticles), anterior maxilla
Complex - disorganised mass of dental tissues, posterior mandible
