Odontogenic Tumours Flashcards
(32 cards)
What are the 3 types of classification of odontogenic tumours?
Epithelial
Mesenchymal
Mixed- epithelial and mesenchymal
Only mixed tumours can have dentine/enamel formation
- due to concept of induction.
Why can only mixed tumours have dentine/enamel formation?
Because of the process of induction.
Dentine is mesenchymal in origin, from odontoblasts, and is the first dental hard tissue to form.
Ameloblasts mature and start laying down enamel only once the dentine has been laid down.
Presence of dentine is important for the induction of maturation of ameloblasts and formation of enamel.
Give examples of odontogenic tumours that a re epithelial in origin?
Ameloblastoma
Adenomatoid odontogenic tumour
Calcifying epithelial odontogenic tumour.
Give examples of odontogenic tumour that is mesenchymal in origin?
Odontogenic myxoma
Giv example of odonotgenic tumour that is mixed in origin?
Odontoma
What is an ameloblastoma?
Benign epithelial tumour/
Locally destructive but slow growing
Typically painless.
What is the aetiology of an ameloblastoma?
Most common in 4th-6th decade
80% occur in the posterior mandible
More common in males than females
What is the radiological presentation of an ameloblastoma?
Margins- well defined, corticated. Potentially scalloped.
May be multi cystic or uni cystic
- if multi-cystic- may have a soup bubble appearance.
Primarily radiolucent.
Will cause displacement of adjacent structures.
Thinning of bony cornices
Knife edge external root resorption.
Histologically, what are the different types of ameloblastoma?
Follicular
Plexiform
Desmoplastic
Describe the histological features of a follicular ameloblastoma?
Neoplastic epithelium is arranged into follicles- look like remnants of the enamel organ.
- Stellate reticulum within the follicle.
- Ameloblast-like cells are surrounding the peripherary- reversed polarity.
Fibrous tissue background.
Cystic changes within the island
- Cystic breakdown.
Changes within the stellate area
- Cystic changes
- Mucous metaplasia
- Granular cell changes.
Why is there a high recurrence rate for ameloblastoma?
There is no connective tissue capsule in an ameloblastoma
- the cells can grow and infiltrate into the jaw bone.
What is the management for an ameloblastoma?
Surgical resection with margin- recurrence relatively common- 15%.
What is the risk of malignant transformation for ameloblastoma?
Less than 1% of cases.
Ameloblastic carcinoma.
What is an adenomatoid odontogenic tumour?
Benign epithelial tumour
What is the aetiology for an adenomatoid odontogenic tumour?
Most common in 2nd decade
More common in females than males
Majority occur in the anterior maxilla.
Describe the presentation of an adenomatoid odontogenic tumour?
Mostly associated with an unerupted tooth- commonly the maxillary canine.
Similar to a dentigerous cyst except it usually attaches apical to the ACJ (dentigerous cyst attaches at the ACJ).
Impeded eruption of the tooth that it encompasses.
Unilocular radiolucency.
Well-defined, corticated margins.
Majority have internal calcifications/radiopacities.
May displace adjacent structures but root resorption is rare.
Describe the histological features of an adenamatoid odontogenic cyst?
Epithelial cells are arranged in a duct-like structure, sometimes may present in sheets.
Well developed fibrous capsule surround the cells.
- makes recurrence rate low.
What radiological factors would make you think it was an adenomatoid odontogenic tumour and not simply the dental follicle?
Tumour won’t be symmetrical
Tumour will go apical to the ACJ.
What is a calcifying epithelial odontogenic tumour?
Benign epithelial tumour
Describe the aetiology of a calcifying epithelial odontogenic tumour.
Most common in 5th decade
More common in males than females
Posterior mandible is the most common site.
How does a calcifying epithelial odontogenic tumour present?
Often asymptomatic
Usually associated with an unerupted tooth
Radiolucency often with internal radiopacities.
Variable radiographic appearance.
What is an odontogenic myxoma?
Benign mesenchymal tumour
Describe the aetiology go an odontogenic myxoma.
Most common in 3rd decade
Equal incidence in males and females
More common in the mandible than the maxilla
How does an odontogenic myxoma present?
Well-defined radiolucency +/- thin corticated margin.
Smaller lesions are unilocular but larger lesions are multilocular with scalloped margins.
- Tennis racket appearance of internal septae.
Scallops between teeth but larger lesions may cause displacement.
