BDS4 Odontogenic Tumours

Question 1

describe odontogenic tumours?

Answer 1

• Majority asymptomatic
  *Often discovered due to non-eruption of teeth, late-stage bony expansion or imaging for other reasons (i.e. incidental)
  *Pain usually secondary to infection or pathological fracture
• Mostly arise within the bone of the jaws

Question 2

what is classification of odontogenic tumours? and example of each?

Answer 2

3 groups based on tissue origin
- epithelial - ameoblastoma
- mesenchymal - Odontogenic myxoma
- mixed (epithelium and mesenchyme) - odontoma

Question 3

what can only mixed tumours have

Answer 3

dentine/enamel formation

Question 4

what are odontogenic sources of epithelium?

Answer 4

• Rests of Malassez
  *Remnants of Hertwig’s epithelial root sheath
• Rests/glands of Serres
  *Remnants of the dental lamina
• Reduced enamel epithelium
  *Remnants of the enamel organ

Question 5

what are types of epithelial odontogenic tumours?

Answer 5

Ameloblastoma
Adenomatoid odontogenic tumour
Calcifying epithelial odontogenic tumour

Question 6

what are most odontogenic tumours?

Answer 6

• > 50% of cases are either ameloblastoma or odontoma

Question 7

what are radiograph appearences like of odontogenic tumours?

Answer 7

highly variable
* Entirely radiolucent mixed entirely radiopaque

Question 8

what is an ameloblastoma? incidence

Answer 8

• Benign epithelial tumour
  *Locally destructive but slow-growing
  *Typically painless
  incidence
• 40-60
• posterior mandible and male

Question 9

types of ameloblastoma?

Answer 9

Radiological
* Multicystic (85-90%)
* Unicystic
*Younger patients
*Lower recurrence risk
Histological
* Follicular
* Plexiform
* Desmoplastic
* (Several other less common types

Question 10

what is this?

Answer 10

ameloblastoma

Question 11

describe structure ameloblastoma?

Answer 11

• Margins
  *Well-defined, corticated
  *Potentially scalloped
• Multicystic type
  *May have thick, curved septa → “soap bubble” appearance
• Primarily radiolucent (but rare variants can be mostly radiopaque)
• Adjacent structures
  *Displacement
  *Thinning of bony cortices
  *“Knife edge” external root resorption

Question 12

what is histology of follcular ameoloblastoma?

Answer 12

Ameloblast-like cells
Stellate reticulum like tissue
Cystic changes
Fibrous tissue

Question 13

what is histology of plexiform ameloblastoma?

Answer 13

Ameloblast-like cells
Stellate reticulum like tissue
Fibrous tissue

Question 14

what is management of ameloblastoma?

Answer 14

• Surgical resection with margin
• Recurrence relatively common
• Risk of malignant transformation
  *<1% of cases
  *Ameloblastic carcinoma

Question 15

what is adenomatoid odontogenic tumour? incidence?

Answer 15

• Benign epithelial tumour
  Unilocular radiolucency with internal calcifications around crown of unerupted maxillary canine” is classic presentation
• incidence
  -20s
  -females more than males
  -anterior maxilla

Question 16

what is presentation of adenomatoid odontogenic tumour?

Answer 16

• 75% associated with unerupted tooth
  -commonly upper canine
• Unilocular radiolucency
• Majority have internal calcifications/radiopacities
• Margins well-defined & corticated/sclerotic
• May displace adjacent structures

Question 17

what is histology of adenomatoid odontogenic tumour?

Answer 17

• distinctive with patchy calcification
• duct like structure

Question 18

what is this

Answer 18

adenomatoid odontogenic tumour

Question 19

what is Calcifying epithelial odontogenic tumour?

Answer 19

• Benign epithelial tumour
  incidence
  -50s
  -males and posterior mandible

Question 20

what is presentation of Calcifying epithelial odontogenic tumour?

Answer 20

• Slow-growing but can become large
• Half are associated with an unerupted tooth
• Radiolucency often with internal radiopacities
  *Calcifications of varying sizes
• Variable radiographic presentation otherwise
  *Unilocular / multilocular
  *Margins: well-defined / poorly-defined
  *Internal septa: none / fine / coarse

Question 21

what is odontogenic myxoma?

Answer 21

• Benign mesenchymal tumour
  incidence
  -30s
  -females and males equal
  -mandible more

Question 22

what is Odontogenic myxoma presentation?

Answer 22

• Well-defined radiolucency +/- thin corticated margin
  *Smaller lesions unilocular
  *Larger lesions multilocular with scalloped margins
  *“Soap bubble” appearance
• Slow growth along bone before causing notable
  bucco-lingual expansion
• Scallops between teeth but larger lesions may
  cause displacement

Question 23

what is histology of Odontogenic myxoma?

Answer 23

• Loose myxoid tissue with stellate cells
• May contain islands of inactive
  odontogenic epithelium
• No capsule → locally invasive

Question 24

what is management of Odontogenic myxoma?

Answer 24

• Curettage or resection (depending on size)
• High recurrence rate: 25%
  *Follow-up important
  *Lower recurrence rate if unilocular

Question 25

what is odontoma? incidence

Answer 25

• Benign mixed “tumour”
  *Technically a hamartoma
  *Malformation of dental tissue
• Similarities to teeth
  **Mature to a certain stage (i.e. do not grow indefinitely)
  **Can be associated with other odontogenic lesions (e.g. dentigerous cysts)
  **Surrounded by dental follicle
  **Lie above inferior alveolar canal
  incidence
• 20s
• females and males equal

Question 26

what are types of odontoma?

Answer 26

1. Compound odontoma
   * Ordered dental structures
   * May appear as multiple “mini teeth” (i.e. denticles)
   * More common in anterior maxilla
2. Complex odontoma
   * Disorganised mass of dental tissues
   * More common in posterior body of mandible

Question 27

what is this?

Answer 27

Calcifying epithelial odontogenic tumour (CEOT)

Question 28

what is this?

Answer 28

Odontogenic myxoma

Question 29

what is this?

Answer 29

odontoma