Odontogenic tumours

Question 1

How can odontogenic tumours be discovered?

Answer 1

• non eruption of teeth
• incidental finding (from imaging for other reasons_
• Pain due to infection or secondary infection
• late stage bony expansion

Question 1

What are the incidence of odontogenic tumours?

Answer 1

They are rare (1%)
Mostly are benign (100:1)
Majority are asymptomatic
Mostly arise in bone (rare cases can be within the surrounding soft tissue)

Question 2

What is the classification of odontogenic tumours?

Answer 2

• epithelial
  -mesenchymal
• mixed (epithelium and mesenchyme)

Question 3

What type of tumours can have dentine/enamel formation?and why?

Answer 3

mixed tumours due to the concept of induction

Question 4

What are the odontogenic sources of epithelium?

Answer 4

• Rests of malassez - remnants of hertwig’s
• Rests of serres - remnants of the dental lamina
• Reduced enamel epithelium - remnants of the enamel organ

Question 5

Give examples of odontogenic epithelial tumours?

Answer 5

Ameloblastoma
adenomatoid odotogenic tumour
Calcififying epithelial odontogenic tumour

Question 6

Give examples of mesenchymal tumours

Answer 6

• odontogenic myxoma

Question 7

Give examples of mixed tumours

Answer 7

Odontoma

Question 8

What is ameloblastoma?

Answer 8

• benign epithelial tumour
• locally destructive
• slow growing
• typically painless

Question 9

incidence of ameloblastoma?

Answer 9

1% of oral and maxillofacial tumours
- most common in 4th and 6th decades
- 8-% occur in posterior mandible
- more in males to females

Question 10

What are the types of ameloblastoma?

Answer 10

Radiological :
multicystic
unicystic

Histological:
Follicular
plexiform
desmoplastic

Question 11

How would you describe the margins of ameloblastoma?

Answer 11

• well-defined and corticated
• potentially scalloped

Question 12

How would you describe multicystic ameloblastoma?

Answer 12

• may have thick/curved septa with soap bubble appearance

Question 13

What are the dental effects of ameloblastoma?

Answer 13

• can cause displacement of adjacent structures
• can cause thinning of bony cortices
• can cause knife edge external root resorption

Question 14

What is the histology of follicular ameloblastoma?

Answer 14

• Ameloblast like cells
• stellate reticulum like tissue
• cystic changes
• Fibrous tissue

Question 15

What is the histology of plexiform ameloblastoma?

Answer 15

• ameloblast like cells
• stellate reticulum like tissue
• fibrous tissue

Question 16

What is the management of ameloblastoma?

Answer 16

• surgical resection with margin
• recurrence is common
• <1% may tranform to malignancy (ameloblastic carcinoma)

Question 17

What is adenomatoid odontogenic tumour?

Answer 17

• a benign epithelial tumour
• unilocular radiolucency with internal calcifications around crown of unerupted maxillary canine

Question 18

How can adenomatoid odotogenic tumour present?

Answer 18

• mostly associated with unerupted tooth (commonly maxillary canine)
• Unilocular radiolucency
• mostly have internal calcification and radiopacities
• margins are well defined and coticated
• May displace adjacent structured but external root resorption is rare

Question 19

What is the difference between adenomatoid odontogenic tumour and dentigerous cyst?

Answer 19

AOT attached to apical to cemento-enamel junction

Question 20

What is the histology of AOT?

Answer 20

• patchy calcification
• duct like structure

Question 21

What is calcifying epithelial odontogenic tumour?

Answer 21

• Benign epithelial tumour
• AKA pindborg tumour
• commonly affecting posterior mandible

Question 22

What is the presentation of CEOT

Answer 22

• slow growing (can become large)
• half are associated with an unerupted tooth
• radiolucency with internal radiopacities
• can be uni ocular or multilocular

Question 23

Describe the margins of CEOT ?

Answer 23

can be well defined or poorly defined with internal septa or without

Question 24

What is odontogenic myxoma?

Answer 24

it is a benign mesenchymal tumour more common in mandible

Question 25

What is the presentation of odontogenic myxoma?

Answer 25

• well defined radiolucency with thin corticated margin
• can be uniocular (small) or multiocular (large)
• tennis racket internal septa is suggestive of myxoma

Question 26

What are the dental effects of odontogenic myxoma?

Answer 26

• buccoliingual expanssion
  may cause external root resorption but this rare

Question 27

What is the histology of odontogenic myxoma?

Answer 27

• loose myxoid tissue with stellate cells
• may contain islands of inactive odontogenic epithelium
• no capsule -> locally invasive

Question 28

What is the management of odontogenic myxoma?

Answer 28

Curettage or resection (depending on size)
- it has a high recurrance rate (25%) - lower if unilocular

Question 29

What is odontoma?

Answer 29

• a benign mixed tumour
• technically a hamartoma
• a malformation of dental tissue (enamel, dentine , cementum and pulp)

Question 30

What are the similarities of an odontoma to teeth?

Answer 30

• they ature to a certain stage
• can be associated with other dental lesions such as dentigerous cysts
• surrounded by dental follicle
• lie above inferior alveolar canal

Question 31

What are the types of odontoma?

Answer 31

1. Compound
   - ordered dental structures
   - Appear as multiple mini teeth (denticles)
   - more common in anterrior maxilla
2. Complex odontoma
   - disorganised mass of dental tissues
   - more common in posterior body of mandible
   compound are more common than complex

Question 32

Histologically