odontogenic tumours Flashcards
why/how are most odontogenic tumours discovered
non eruption of teeth
late stage bony expansion
incidental finding due to imaging for another reason
why can only mixed odontogenic tumours have enamel and dentine formation
due to concept of induction
they stimulate each others growth
what are the 5 odontogenic tumours
epi - ameloblstoma, calcifying epithelial OT, adenomatoid OT
mes - odontogenic myxoma
mixed - odontoma
radiographic presentation of ameloblastoma
well defined, corticated margins that may be scalloped
primarily radiolucent
knife edge ERR
displacement of adjacent structures
thinning of bony cortices
what direction do ameloblastomas grow
in all directions fairly equally
how are ameloblastomas classified radiographically
multicystic - may have curved septae giving soap bubble appearance (90% cases)
unicystic - younger patients, lower recurrence risk, no scalloped margins
2 most common histological forms of ameloblastoma
follicular
plexiform
what form of ameloblastoma may present as a radiopaque lesion
desmoplastic
follicular ameloblastoma
islands present within fibrous tissue background
islands bordered by ameloblast like cells which have darkly staining nucleus (hyperchromatic), columnar in shape and palisading arrangement
tissue in middle of islands will resemble stellate reticulum of tooth germ
plexiform ameloblastoma
ameloblast like cells almost back to back with minimal stellate reticulum like tissue between
fibrous tisse will also be present
do ameloblasts have a fibrous tissue capsule
no
cells can infiltrate surrounding jaw bone - difficult to eradicate, recurrence rates up to 15%
how are ameloblastomas treated
surgical resection with margin
classic presentation of an adenomatoid odontogenic tumour
unilocular radiolucency with internal calcifications around crown of an unerupted maxillary canine
common epidemiology of adenomatoid odontogenic tumour
F>M
anterior maxilla
majority associated with unerupted canine
teenagers
dentigerous cyst vs AOT
dentigerous cyst attaches at ECJ
AOT attaches apical to ECJ
radiographic appearance of AOT
unilocular radiolucency
majority have some internal radiopacities which increase as tumour matures
margins are well defined and corticated
may displace adjacent structures
ERR is rare
AOT histology
epithelial cells may be arranged in duct like or rosette like structures
minimal connective tissue present
degree of calcification may be noted
do AOTs have a capsule
yes - well developed fibrous capsule - low recurrence rate
management of AOT
majority treated by enucleation - associated tooth also removed
can also be treated with conservative local excision
what are calcifying epithelial odontogenic tumours also known as
pindborg tumours
odontogenic myxoma epidemiology
20s
F>M
mandible>maxilla
radiographic presentation of odontogenic myxoma
well defined radiolucency
small lesions unilocular, larger lesions multilocular with scalloped margins.
ERR rare
larger lesions may cause displacement
larger lesions may have interal ‘tennis racket’ appearance due to septae
if present in maxilla what may be seen in large odontogenic myxoma
obliteration of maxillary sinus
histology of odontogenic myxoma
made up of myxoid tissue which is loose and would be gelatinous in consistency
stellate cells present within myxoid tissue but few in number
may be islands of inactive epithelial cells (not dividing)
do odontogenic myxomas have a capsule
no capsule
locally invasive
25% recurrence rate!
what similarities to teeth do odontomas have
mature to a certain stage (dont grow indefinetly)
can be associated with other odontogenic lesions e.g dentigerous cyst
surrounded by dental follicle
lie above IAC
what syndrome is associated with multiple odontomas
gardners syndrome
what are the 2 different types of odontoma
compound
complex
(compound more common 2:1)
radiographic presentation of odontomas
initally radiolucent but progressive deposition of radiopaque material as mineralisation of dental tissues occurs
mature lesions surrounded by dental follicle
compund may appear as multiple ‘mini teeth’ - denticles
histological appearance of odontomes
both compound and complex will have dental hard tissue
dentine often seen
may be element of soft tissue present
as enamel is organic, it is dissolved by acids during slide preparation so enamel spaces are seen instead
enamel and histology in odontomes
as enamel is inorganic it is dissolved out by acids during slide preparation
if enamel fully calcified - will appear as spaces
if still a large organic content then this may show within enamel space - ‘fishscale’ appearance
