Odontogenic Tumours

Question 1

Ameloblastoma:
- Benign or malignant?
- Painful or not?
- Expansive?
- Can it resorb teeth?

Answer 1

Benign
Not painful
Expansive buccally
May displace and/or resorb teeth

Question 2

What are the 3 types of tumors?

Answer 2

1) Odontogenic epithelium without odontogenic ectomesenchyme

2) Odontogenic epithelium with odontogenic ectomesenchyme

3) Odontogenic epithelium without mesenchyme

Question 3

How do we differentiate odontogenic tumours?

Answer 3

• Age and sex of patient
• Size and anatomical position
• Size
• Shape: unilocular/multilocular
• Outline/edge of periphery
• Relative radiodensity and internal structure
• Time present
• Decision on biopsy

Question 4

What site of the mouth do ameloblastomas tend to form?

Answer 4

Posterior Mandible

Question 5

Are ameloblastomas multilocular or unilocular?

Answer 5

Multilocular

Question 6

What is the main differential for ameloblastoma?

Answer 6

Odontogenic keratocyst

Question 7

Why are ameloblastomas infiltrative?
How are they treated?

Answer 7

• They infiltrate the surrounding bone
• The epithelium extends into the trabeculae of the medullary bone beyond the edge of the cavity

Question 8

How do ameloblastomas present radiographically?

Answer 8

• Rounded, cyst-radiolucent ares
• Smooth, well-defined, corticated margins
• Radiolucent with radio-opaque septa

Question 9

What is the treatment of ameloblastomas?

Answer 9

• Excision with 1cm bone margins

Question 10

Why can ameloblastomas be hard to diagnose?

Answer 10

Sometimes present as a unicystic lesion.
Occurs in young people.
These can be enculated without reoccurance.

Question 11

Is a calcifying epithelial odontogenic cyst formed from epithelium or mesenchymal cells or both?

Answer 11

Epithelium

Question 12

What does a calcifying epithelial odontogenic tumour contain?

Answer 12

Amyloid proteins secreted by the odontogenic epithelium

Question 13

What tissue is ameloblastic fibroma formed from?

Answer 13

• Epithelium and ectomesenchyme

Question 14

What feature can be seen on histology of an adenomatoid odontogenic tumour?

Answer 14

• Duct like spaces

Question 15

What cells can be seen on histology of a calcifying odontogenic cyst?

Answer 15

• Flattened epithelial cells: nuclei remains at centre of the cell where the nuclei used to be
• Nuclei die and form a hole

Question 16

What are the two types of odontomes?

Answer 16

COMPLEX = completely dirogaised enamel and dentine, minimal soft tissues present

COMPOUND = made up of tooth like structures that cluster to form compound tissue.

Question 17

What is an odontogenic fibroma formed from?

Answer 17

Fibrous odontogenic epithelium.
Spindle spaced fibroblasts and bundle of collagen fibres

Question 18

What is an odontogenic myxoma formed from?
Where does it usually form in the jaw?
What is the treatment for this tumour?

Answer 18

• Composed of myxoid connective tissue
• Little collagen and lots of proteoglycan ground substance
• Posterior mandible
• Local resection due to bone permeation

Question 19

What is the main differential of a cementoblastoma?

Answer 19

PAINFUL bony swelling

Question 20

How is a cementoblastoma seen on X ray?

Answer 20

• Radio-opaque circular tumour with a radiolucent outline

Question 21

What are some signs that may lead us to think a tumour is malignant?

Answer 21

• Swelling
• Pain
• Numb lip or palate
• Radiolucency
• Root resorption and bone resorption
• Tooth mobility
• Pathological jaw fracture
• Enlarged lymph nodes
• History of malignancy