Odontogentic Tumors

Question 1

Majority of odntogenic tumours are asymtomatic what are three reasons that they may be found

Answer 1

Non eruption of teeth
Late stage bony expansion
Incidental findings for imaging of other things

Question 2

Only mixed odontogenic tumours can have dentine/enamel formation - this is due to the concept of induction what is this

Answer 2

Often these mixed tumours have dental hard tissues bound within these tumours due to the concept of induction . This is because

First dental hard tissue that gets formed is dentine - this comes from odontoblasts which are mesenchymal in orgin.
Ameloblasts only start forming enamel once the dentine gets laid down
Presence of dentne is important for the induction of maturation of enamel

Question 3

Rests of malassez can be a source of odontogneic tumours, what are they remenants of

Answer 3

Hertwigs epithelial root sheath

Question 4

The rests of serres can be a source of an odontogenic tumour, what are these remenants of

Answer 4

Remnants of the dental lamina

Question 5

What is the dental lamina responsible for

Answer 5

The formation of the tooth germ

Question 6

The reduced enamel epithelium is remenants of what

Answer 6

The enamel organ

Question 7

What are the two most common odomtogenic tumours

Answer 7

Ameloblastoma and odontoma

Question 8

What kind of tumor is an Ameloblastoma

Answer 8

Benign epithelial tumour

Question 9

What are two features of an Ameloblastoma

Answer 9

Slow growing but locallly destructive
Typically painless

Question 10

Radiologically Ameloblastoma can be multi cystic or unicystic - what one has a lower rate of recurrence

Answer 10

The unicystic one

Question 11

What is the characteristic pattern of expansion for an Ameloblastoma

Answer 11

It will expand in all directions equally

Question 12

Ameloblastomas cause displacement and respotion typically of adjacent structures - what is that characteristic appearance of the resorption

Answer 12

Knife edge appearance of external root resorption

Question 13

In terms of the histology what is one of the main reasons rhat Ameloblastomas have such a high recurrence rate

Answer 13

Because they have no connective tissue capsule - cells can therefore grow and infiltrate the jaw bone

Question 14

What is the managment of an Ameloblastoma

Answer 14

Surgical resection with 1cm margin of normal bone

Question 15

Why do we do a 1cm margin when doing a surgical resection in Ameloblastomas

Answer 15

Even tho it is benign we do this due to the high reccurence rate

Question 16

Unilocular radiolucney with internal calcifications around the crown of an unerupted maxillary canine is the classic presentation of what type of odontogenic tumour

Answer 16

Adenomatoid odontogenic tumour

Question 17

What kind of tumour is an adenomatoid odontogenic tumour

Answer 17

A benign epithelial tumour

Question 18

AOT can look similar to a Dentigerous Cyst how can we aim to tell the difference

Answer 18

A Dentigerous cyst is attached at the CEJ of the crown of an unerupted tooth however an AOT will be attached further down the root ( apical to the CEJ)

Question 19

What tooth is an AOT most commonly assoacted with and what clincal problem does it cause

Answer 19

Maxillary canine
Impedes eruption

Question 20

What kind of tumour is a calcifying epithelial odontogenic tumour

Answer 20

Begin epithelial tumour

Question 21

What is the most common location for a CEOT and how may it look Radiographically

Answer 21

Most common in the posterior mandible
Radiolucney with internal radiopacioties - varying in size

Question 22

Name a benign mesenchymal odontogenic tumour

Answer 22

Odontogenic myxoma

Question 23

Tennis racket pattern of septa on a radiograph may indicate what kind of tumour

Answer 23

Odontogenic myxoma - not in all cases

Question 24

How does an odontogenic myxoma tend to expand

Answer 24

Slow growth along bone before causing notable buccally-lingual expansion

Question 25

How may an odontogenic myxoma present histologically

Answer 25

Loose myxoid tissue with stellate cells
No capsule so locally invasive

Question 26

How is an odontogenic myxoma managed

Answer 26

Curettage for smaller lesion
Resection for large lesions

Question 27

Why is follow up with odontogenic myxoma so important - what is the rate of recurrence

Answer 27

High reccurence rate of 25%

Question 28

What kind of tumour is an odontoma

Answer 28

A begin mixed tumour

Question 29

What is an odontoma

Answer 29

A malformation of dental tissue

Question 30

Name 4 similarities of an odontoma to teeth

Answer 30

Mature to a certain stage ( do not grow indefinitely )
Can be associated with other odontogenic lesions ( e.g. Dentigerous cyst)
Surrounded by a dental follicle
Lies above the inferior alveolar canal

Question 31

Name the two types of odontoma and which is more common

Answer 31

Compound
Complex

Compound is more common than complex

Question 32

Describe a compound odontoma

Answer 32

Ordered dental structures
May appear as mutiple mini teeth ; denticles
More common in anterior maxilla

Question 33

Describe a complex odontoma

Answer 33

Disorganised mass of dental tissues - dense radiopacity
More common in posterior body of the mandible

Question 34

What are the two patterns of amelobastomas

Answer 34

Follicular and plexifrom

Question 35

What is the typical descriptive term used to describe and Ameloblastoma on a radiograph?

Answer 35

Soap bubble appearnce

Question 36

Why is surgery required for Ameloblastomas

Answer 36

Because they are relatively radio resistant