Odontogenic Tumours

Question 1

What are the 3 groups of odontogenic tumours based on origin?

Answer 1

Epithelial

Mesenchymal

Mixed

Question 2

Examples of epithelial odontogenic tumours

Answer 2

Ameloblastoma

AOT

CEOT

Question 3

Examples of mesenchymal tumour

Answer 3

Odontogenic myxoma

Question 4

Examples of mixed tumour

Answer 4

Odontoma

Question 5

Name 3 sources of epithelium

Answer 5

Rests of malassez - remnants of HERS

Rests of seres - remnants of dental lamina

REE - remnants of enamel organ

Question 6

Features of amelobastoma

Answer 6

Painless
Locally destructive but slow growing
40-60s
Posterior mandible
M>F

Question 7

Radiological features of ameloblastoma (7)

Answer 7

Multicystic

Soap bubble appearance

Well defined corticated margins

Potentially scalloped

Displaces IAN

Knife edge ERR

Thinning of bony cortices

Question 8

How does ameloblastoma present radiographically in younger patients?

Answer 8

Unicystic - decreased recurrence

Question 9

Histological classification

Answer 9

1. Follicular
2. Plexiform
3. Desmoplastic

• Ameloblast like cells
• Stellate reticulum like tissue
• Fibrous tissue
• No capsule

Question 10

Tx for ameloblastoma

Answer 10

Surgical resection with margin

Risk of malignant transformation

Question 11

Features of CEOT

Answer 11

Common in 50s
M>F
50% UE tooth
Posterior mandible

Question 12

Radiological features of CEOT

Answer 12

Unilocular/multilocular
Margins: well/poor
May have internal septa

Question 13

Features of AOT

Answer 13

Common in 20s
F>M
Majority in anterior maxilla
May displace adjacent structures

Question 14

Radiographic features of AOT

Answer 14

Unilocular radiolucency
May displace adjacent structures

Question 15

Histological features of AOT

Answer 15

Duct like structures
Patchy calcification

Question 16

How to differentiate between AOT and dentigerous cyst?

Answer 16

Dentigerous attaches to CEJ

AOT attaches further down

Question 17

Incidence of odontogenic myxoma

Answer 17

30s
F=M
Mandible>maxilla

Question 18

Presentation of odontogenic myxoma

Answer 18

Well defined radiolucency +/- thin corticated margin

Smaller lesion - unilocular

Larger lesion - multilocular with scalloped margins

Slow growth along bone before causing notable buccolingual expansion

Question 19

Histology of odontogenic myxoma (3)

Answer 19

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

Question 20

Management of odontogenic myxoma (3)

Answer 20

Curettage or resection

High recurrence 25%

Lower rate of unilocular

Question 21

Incidence of odontoma

Answer 21

Most common 20s
F=M

Question 22

Radiographic presentation of odontoma

Answer 22

Malformation of dental tissue (enamel, dentine, cementum + pulp)

Lie above IA canal

Surrounded by dental follicle

Well defined radiopacities

Question 23

Different types of odontoma (2)

Answer 23

1. Compound
   - Ordered dental structure
   - Multiple mini teeth
   - More common in anterior maxilla
2. Complex
   - Disorganised dental tissues
   - More common in posterior body of mandible