Odontogenic Tumours

Question 1

are odontogenic tumours symptomatic

Answer 1

majority are asymptomatic
pain is usually secondary to infection or pathological fracture

Question 2

what are the 3 tissues of origin for odontogenic tumours

Answer 2

epithelial
mesenchymal
mixed (epithelial and mesenchymal)

Question 3

types of epithelial origin odontogenic tumours

Answer 3

ameloblastoma
adenomatoid odontogenic tumour
calcifiying epithelial odontogenic tumour

Question 4

type of mesenchymal odontogenic tumour

Answer 4

odontogenic myxoma

Question 5

type of mixed odontogenic tumours

Answer 5

odontoma

Question 6

what are the 3 odontogenic sources of epithelium

Answer 6

1. rests of malassez (remnants of HERS)
2. rests/glands of serres (remnants of dental lamina)
3. reduced enamel epithelium (remnants of enamel organ)

Question 7

odontogenic tumour radiographic representation

Answer 7

highly variable
- appearance may change as lesion progresses
- some entirely radiolucent, some mixed, some entirely radiopaque

Question 8

what are the 2 most common odontogenic tumours

Answer 8

ameloblastoma
odondotoma

Question 9

ameloblastoma
- what is it
- symptoms
- incidence

Answer 9

• benign epithelial tumour
• typically painless
• most common in 30s-50s, in posterior mandible

Question 10

radiographic features of ameloblastoma

Answer 10

• well defined corticated margins
• potentially scalloped
• primarily radiolucent
• ‘soap bubble appearance’ septae within lesion
• thinning of bony cortices
• adjacent structures may be displaced
• knife edge external root resorption

Question 11

ameloblastoma pattern of growth

Answer 11

expands in all directions fairly equally

Question 12

what are the 3 ways to classify ameloblastomas histologically

Answer 12

follicular
plexiform
desmoplastic (rare)

Question 13

follicular ameloblastoma presentation

Answer 13

follicular = histological classification
islands present within a fibrous tissue background. Islands bordered by ameloblasts.
tissue in middle of follicles resembles stellate reticulum

Question 14

plexiform ameloblastoma

Answer 14

plexiform = histological classification
ameloblast like cells arranged in strands, in between strands may stellate reticulum like tissue.

Question 15

why do ameloblastomas have a high recurrence rate

Answer 15

no connective tissue capsule so can infiltrate surrounding jaw bone

Question 16

ameloblastoma risk of malignancy

Answer 16

<1%

Question 17

adenomatoid odontogenic tumour (AOT)
- what is it
- incidence/ epidemiology
- association

Answer 17

benign epithelial tumour
most common in teens, majority occur in anterior maxilla
majority of cases associated with unerupted tooth

Question 18

differentiating between dentigerous cyst and adenomatoid odontogenic tumour

Answer 18

dentigerous cyst typically attaches at ECJ
AOT typically attaches apical to ECJ

Question 19

radiographic presentation of adenomatoid odontogenic tumour

Answer 19

well defined, corticated margins,associated with an unerupted tooth
may displace adjacent structures
impedes eruption
margins join tooth apical to ECJ

Question 20

most common tooth to be affected by an adenomatoid odontogenic tumour

Answer 20

maxillary canine

Question 21

histological appearance of adenomatoid odontogenic tumour

Answer 21

well developed fibrous tissue capsule
epithelial cells may be arrances in duct like structures or in rosette like appearace.
flecks of radiopacity in radiographs correspond to patchy calcification

Question 22

calcifying epithelial odontogenic tumour

Answer 22

benign epithelial tumour

Question 23

presentation of calcifying epithelial odontogenic tumour

Answer 23

slow growing
50% associated with unerupted tooth
radiolucency with internal radiopacities

Question 24

odontogenic myxoma

Answer 24

benign mesenchymal tumour

Question 25

radiographic presentation of odontogenic myxoma

Answer 25

well defined radiolucency +/- thin corticated margin
scallops between teeth

soap bubble appearance
small lesions unilocular, large lesions multilocular
scallops between teeth
tennis racket appearance of internal septae may be present

Question 26

odontogenic myxoma recurrence rate

Answer 26

high recurrence rate (25%)

Question 27

Odontoma

Answer 27

benign mixed tumour
malformation of dental tissue (enamel, dentine, cementum and pulp)

Question 28

what are the 2 main types of odontoma

Answer 28

compound
complex

Question 29

compound odontoma

Answer 29

ordered dental structuresm more common in anterior maxilla

Question 30

complex odontoma

Answer 30

disorganised mass of dental tissues
more common in posterior mandible