ORAL PATH odontogenic cysts Flashcards
What is a cyst?
a pathological cavity having fluid or semi-fluid content
lined wholly or in part by epithelium
NOT due to accumulation of pus
what is an accumulation of pus called?
an abscess
what are the 2 main classifications of cysts of the jaws?
odontogenic
non-odontogenic
where are odontogenic cysts derived from?
epithelial residues of tooth-forming organ
what are the 2 categories of odontogenic cysts?
inflammatory
developmental
what do teeth develop from?
odontogenic epithelium and neural crest derived ectomesenchyme
what becomes the enamel organ?
dental lamina budding down from the ectoderm
what are the 4 layers of the enamel organ?
inner enamel epithelium
outer enamel epithelium
stellate reticulum
stratum intermedium
what layer of the enamel organ forms ameloblasts?
inner enamel epithelium
what cells develop into the pulp?
ectomesenchyme
how is dentine laid down?
by odontoblasts which are differentiating pulpal cells
at what point is the enamel matrix laid down?
after dentine is laid down
how is root formation mapped out?
after crown formation, the enamel organ reduces to form the root sheath of hertwig
what are remnants of the dental lamina known as?
glands of serres
what are remnants of the root sheath of hertwig known as?
cell rests of malassez
what are the types of inflammatory odontogenic cysts?
radicular cysts (apical, lateral, residual)
inflammatory collateral cysts (paradental, mandibular buccal bifurcation)
what is the most common type of jaw cyst?
radicular cyst (55%)
where do radicular cysts arise from?
epithelial proliferation and cyst formation within some periapical granulomas
where is the most frequent location of radicular cysts?
anterior maxilla
do radicular cysts come with symptoms?
often none
slow growing swelling
what is the one diagnostic criteria for a radicular cyst?
must be associated with a non-vital tooth
radiographic features of radicular cyst?
usually at the apex (unless associated with a lateral canal)
well-circumscribed unilocular radiolucent lesion
what is the pathogenesis of a radicular cyst?
proliferation of epithelium in response to inflammation
cysts enlarges due to osmotic pressure
local bone resorption
what are the key histopathological features of radicular cysts?
cholesterol clefts
haemosiderin
treatment for radicular cyst?
small cysts may resolve after RCT/XLA/periradicular surgery
enucleation
marsupialisation for very large lesions
what is enucleation?
entire lesion removed
what is marsupialisation?
converting cyst into a pouch to let it drain prior to enucleation
what is a lateral radicular cyst?
radicular cyst arising from a lateral root canal branch of a non-vital tooth
what is a residual cyst?
radicular cyst that persists after xla of the associated non-vital tooth
what are the 2 variants of inflammatory collateral cysts and where do you find them?
paradental cyst - lower 3rd molars
mandibular buccal bifurcation cyst - lower 1st or 2nd molars
aetiology of inflammatory collateral cysts?
inflammation associated with pericoronitis
or
enamel spur on buccal aspect of involved tooth
what exacerbates inflammatory collateral cysts?
food impaction
what type of collateral cyst is more common?
paradental
what are the clinical features of an inflammatory paradental cyst?
chronic pericoronitis association
associated with vital tooth
well-demarcated radiolucency
what are clinical features of mandibular buccal bifurcation inflammatory cysts?
painless swelling
associated with tooth tilted buccally with deep perio pocket
well demarcated buccal radiolucency
treatment of mandibular buccal bifurcation cysts?
enucleation
removal of 8s and paradental cyst
list the types of developmental odontogenic cysts?
odontogenic keratocyte
dentigerous cyst/ eruption cyst
lateral periodontal cyst and botryoid odontogenic cyst
glandular odontogenic cyst
gingival cysts
calcifying odontogenic cyst
orthokeratinised odontogenic cyst
where do you find most odontogenic keratocysts?
posterior mandible
are odontogenic keratocysts symptomatic?
only if they are infection or when cortical bony expansion
radiographic features of odontogenic keratocysts?
well-defined radiolucency
uni or multi locular lesion
aetiology of odontogenic keratocysts?
remnants of the dental lamina (glands of serres)
mutation/ inactivation of PTCH1 gene, chromosome 9
activation of SHH signaling pathway = aberrant cell proliferation of epithelium
what was the classification for odontogenic keratocysts in 2005?
keratocystic odontogenic tumour
why did are odontogenic keratocysts no longer called keratocystic odontogenic tumours?
there isnt enough evidence to support a neoplastic origin
what is gorlin syndrome?
naevoid basal cell carcinoma syndrome
what syndrome do keratocysts present in?
Gorlin syndrome
what is the histopathology of odontogenic keratocysts?
cystic lesion
keratinised stratified squamous epithelial lining
corrugated parakeratin layer
no inflammation (unless secondary infection)
what type of cyst is an odontogenic keratocyst?
benign developmental cyst
treatment options for odontogenic keratocysts?
marsupialisation
enucleation
marsupialisation + enucleation
enucleation + carnoys solution
enucleation + cryotherapy
resection
what is carnoys solution?
eliminates any cyst/ daughter cysts leftover
what is the best tx option for odontogenic keratocysts?
no evidence
some evidence to support lower recurrence rate with enucleation + carnoys solution and for resection
what is a dentigerous cyst?
developmental cyst
encloses all or part of a crown of unerupted tooth
attached to the ACJ
affects impacted teeth or teeth late to erupt
are dentigerous cysts symptomatic?
symptom free until significant swelling or if infected
potential ballooning expansion
radiographic features of dentigerous cysts?
well-circumscribed unilocular radiolucency associated with crown of unerupted tooth
histopathology of dentigerous cyst?
non-keratinised stratified squamous epithelial lining
fibrous capsule
no inflammation unless secondary infection
treatment for dentigerous cysts?
enucleation
exposure/ transplantation/ xla of associated tooth
what must you include on the pathology request form if suspect a dentigerous cyst?
clinical attachment of lesion to ACJ of unerupted tooth
what is an eruption cyst?
dentigerous cyst arising in the extra-alveolar location
clinical features of eruption cysts?
typically seen in children
deciduous and permanent molars
present as bluish swelling
treatment options for eruption cysts?
none
exposure of erupting tooth
clinical features of lateral periodontal cyst?
uncommon
arise in adjacent to vital tooth
canine and premolar region of mandible
usually symptom free, incidental finding
well-circumscribed radiolucency in PDL
what do lateral periodontal cysts arise from?
cell rests of malassez
treatment for lateral periodontal cysts?
enucleation
recurrence is rare
what is a botryoid odontogenic cyst?
very rare multicystic variant of lateral periodontal cyst
botryoid = ‘bunch of grapes’ - polycystic appearance
how do botryoid odontogenic cysts present radiographically?
multilocular radiolucency
where do you find botryoid odontogenic cysts?
mandibular premolar, canine region
clinical features of glandular odontogenic cysts?
very rare
anterior mandible
multilocular
what malignant condition must glandular odontogenic cysts be differentiated from?
central mucoepidermoid carcinoma
treatment for glandular odontogenic cysts?
enucleation but high recurrence rate
what are gingival cysts?
developmental cysts which occur in infants
superficial keratin-filled cysts in the gingivae of newborns
what causes gingival cysts in infants?
proliferation of dental lamina remnants (glands of serres)
what do gingival cysts in infants present as?
white nodules
treatment for gingival cysts?
none
usually disappear in a few weeks
do you get gingival cysts in adults?
very rarely
treatment for gingival cysts in adults?
simple excision
what is a calcifying odontogenic cyst?
painless swelling of the jaw which can present with tooth displacement and resorption
aetiology of calcifying odontogenic cysts?
arises from dental lamina
what was the 2005 classification for calcifying odontogenic cysts?
neoplasm
treatment for calcifying odontogenic cyst?
enucleation
recurrence is rare
clinical features of orthokeratinised odontogenic cysts?
in the mandible
painless swelling of the jaw
well-defined unilocular radiolucency
aetiology of orthokeratinised odontogenic cysts?
pathogenesis uncertain but likely derives from dental lamina
treatment for orthokeratinised odontogenic cysts?
enucleation
recurrence is rare
in what cases, would an OKC resemble a radicular cyst?
if secondarily inflamed
