Cysts of the Jaws Flashcards
What is a cyst?
a pathological cavity having fluid, semi-fluid or gaseous contents and which is not created by the accumulation of pus
cysts - features
diverse group of lesions
symptomatic or asymptomatic
slow or fast growing
indolent or destructive
almost all benign
Cysts - signs and symptoms
often asymptomatic unless infected
Cysts - initial radiographs that can be taken to investigate
periapical
occlusal
panoramic
supplemental radiographs that can be taken to investigate cysts
CBCT
facial radiographs
Radiographic features of cysts
shape
- often spherical or egg-shaped
- most grow by hydrostatic pressure
margins
- often well defined
- often corticated
locularity
- ofren unilocular
multiplicity
- can be single, bilateral or multiple
- multiple cysts may indicate a syndrome
inclusion of unerupted teeth
Cysts - effect on surrounding anatomy
displacement of cortical plates, adjacent teeth, maxillary sinus, inferior alveolar canal
- variable degree and pattern of growth
- root resorption may occur with chronic cysts
cysts - radiographic signs of secondary infection
may lose definition and cortication
typically associated with clinical signs and symptoms
Classification of cysts
structure
- epithelium lined vs no epithelial lining
origin
- odontogenic vs non odontogenic
pathogenesis
- developmental vs inflammatory
give examples of developmental odontogenic cysts
dentigerous cyst and eruption cysts
odontogenic keratocyst
lateral periodontal cyst
give examples of odontogenic inflammatory cysts
radicular cyst and residual cyst
inflammatory collateral cysts
- paradental cyst
- buccal bifurcation cysts
give an example of a non-odontogenic developmental cyst
nasopalatine duct cyst
give examples of non-devleopmenal non-odontogenic cysts
solitary bone cysts
aneurysmal bone cysts
*no epithelial lining = not true cysts
features of odontogenic cysts
occur in tooth bearing areas
most common cause of bony swelling in the jaws
- >90% of all cysts in oral and maxillofacial region
all lined with epithelium
odontogenic sources of epithelium
rests of malaseez
- remnants of Hertwig’s epithelial root sheath
rests of Serres
- remnants of the dental lamina
reduced enamel epithelium
- remnants of the enamel organ
most common odontogenic cysts
radicular cyst (and residual cyst)
- 60% of odontogenic cysts
dentigerous cyst (and eruption cyst)
- 18%
odontogenic keratocyst
- 12%
radicular cysts features
inflammatory odontogenic cyst
- always associated with a non-vital tooth
- initiated by chronic inflammation at apex of tooth due to pulp necrosis
sometimes called dental cysts or periapical cysts
radicular cysts - incidence
most common in 4th and 5th decades
60% maxilla, 40% mandible
can involve any tooth
radicular cyst - presentation
often asymptomatic
may become infected
- pain
typically slow growing with limited expansion
radicular cysts vs periapical granulomas
difficult to differentiate radiographically
radicular cysts typically larger
if radiolucency diameter >15mm = 2/3 cases will be radicular cysts
radicular cysts radiographic features
well defined, round/oval radiolucency
corticated margin continuous with lamina dura of non-vital tooth
larger lesions may cause displace adjacent structures
long-standing lesions may cause external root resorption and/or contain dystrophic calcification
radicular cyst histology
epithelial lining - often incomplete
connective tissue capsule
inflammation in capsule
how may radicular cysts form?
proliferating epithelium with central necrosis
or
epithelium surrounds fluid areas
how do radicular cysts grow?
osmotic effect with semi-permeable wall
cytokine mediated growth
name 2 variants of radicular cysts
residual cysts
lateral radicular cysts
what is a residual cyst?
when a radicular cyst persists after loss of tooth
- or after tooth is successfully root canal treated
what is a lateral radicular cyst?
a radicular cyst associated with an accessory canal
- located at side of tooth instead of apex
inflammatory odontogenic cysts - features
associated with a vital tooth
collective term for
- paradental cyst
- buccal bifurcation cyst
paradental cysts typically occur…
at distal aspect of partially erupted mandibular third molar
buccal bifurcation cysts typically occur…
at buccal aspect of mandibular first molar
dentigerous cyst features
developmental odontogenic cyst
associated with crown of unerupted (and usually impacted) tooth
- e.g. mandibular 3rd molars, maxillary canines
cystic change of dental follicle
dentigerous cyst incidence
more common in 2nd-4th decades
male > female
mandible > maxilla
Dentigerous cyst radiological features
corticated margins attached to cemento-enamel junction of tooth
- larger cysts may begin to envelop root of tooth
may displace involved tooth
tend to be symmetrical initially
- larger cysts may begin to unilaterally expand
- variable displacement of cortical bone/bony expansion
dentigerous cyst - histology
thin non-keratinised stratified squamous epithelium
- may resemble radicular cyst if inflamed
how to tell the difference between a dentigerous cyst and an enlarged follicle
consider cyst if follicular space 5mm or more
- measure from surface of crown to edge of follicle
- normal follicular space typically 2-3mm
- assume cyst if >10mm
consider cyst if radiolucency is asymmetrical
eruption cyst features
variant of dentigerous cyst
- continued within soft tissue rather than bone
associated with an erupting tooth
- more commonly incisors
- almost exclusively affects children
odontogenic keratocyst features
developmental odontogenic cyst
no specific relationship to teeth
- high recurrence rate
odontogenic keratocyst incidence
more common in 2nd and 3rd decades
male>female
mandible>maxilla (3:1)
posterior >anterior
odontogenic keratocyst radiographic features
often have scalloped margins
25% are multilocular
often cause displacement of adjacent teeth
- root resorption uncommon
characteristic expansion
- can have significant mesio-distal expansion without bucco-lingual expansion
odontogenic keratocyst pre operative diagnostic test
cyst aspirate
- containes squames
- low soluble protein content
odontogenic keratocyst histology
basal palisading
parakeratosis
loss of keratin if inflamed
basal cell naeuvus syndrome - presentation
multiple odontogenic keratocysts
multiple basal cel carcinomas
calcification of inter cranial dura mater
cysts histologically identical to non-syndromic form but often occur as a younger age e.g. 15 years
give examples of non-odontogenic cysts
nasopalatine duct cyst
- most common
solitary bone cyst
aneurysmal bone cyst
nasopalatine duct cyst features
developmental non-odontogenic cyst
arises from nasopalitine duct epithelial remnants
occurs in anterior maxilla
aka incisive canal cyst
nasopalatine duct cyst incidence
more common in 4th to 6th decades
male > female
nasopalatine duct cyst presentation
often asymptomatic
patients may note ‘salty’ discharge
larger cysts may displace teeth or cause swelling in palate
always involves midline but not always symmetrical
naspalatine duct cyst - histology
variable epithelial lining
- non-keratinised stratified squamous and modified respiratory
nasopalatine duct cyst; radiographic features
periapical or/and standard maxillary occlusal
- corticated radiolucency between/over roots of central incisors
- often unilocular
- may appear ‘heart shaped’ due to superimposition of anterior nasal spine
CBCT may be indicated if better visualisation of cyst required for surgical planning
Cyst vs incisive fossa
incisive fossa
- may or may not be visible radiographically
- midline, oval shaped radiolucency
- typically not visibly corticated
transverse diameter can be considered in absence of clinical issues:
<6mm assume incisive fossa
6-10mm consider monitoring
>10mm = suspect cyst
What is a solitary bone cyst?
non-odontogenic cyst without an epithelial lining
aka simple/traumatic/haemorrhagic bone cyst
solitary bone cyst incidence
most common in 2nd decade
male>female
mandible»maxilla
can occur in association with other bone pathology
- e.g. fibre-osseous lesions
solitary bone cyst - clinical presentation
- usually asymptomatic - incidental finding
- rarely pain or swelling
solitary bone cyst - radiological features
majority in premolar/molar region of mandible
- can also occur in non-tooth bearing areas
variable definition and cortication
may have scalloped margins giving a pseudooculuar appearance
may project up between the roots of adjacent teeth
what is a stafne cavity?
not a cyst but commonly mistaken as one
- depression in the bone
- only occur in mandible, almost exclusively lingual
- contains salivary or fatty tissue
stafne cavity presentation
more common in 5th and 6th decades
often in angle or posterior body of mandible
often inferior to inferior alveolar canal
asymptomatic
well-defined, often corticated radiolucency
rarely displaces adjacent structures
Cysts - how to obtain material for histology
aspiration biopsy
- drainage of contents
incisional biopsy
- partial removal
excisional biopsy
- complete removal
What is required for an aspiration biopsy
wide bore needle
5-10ml syringe
How cyst fluid may determine the type of cyst
clear or straw coloured fluid found in inflammatory or developmental cysts
white or cream semi-solid may indicate keratocyst
purpose of an incisional biopsy
to obtain a sample of the lining for histological analysis
incisional biopsy method
usually under LA
select region where lesion appears superficial
raise mucoperiosteal flap
remove bone as required
- using round bur
incise and remove section of lining
may be combined with marsupialisation
Cysts - outline surgical options
enucleation
- removal of all cystic lesion
marsupialisation
- creation of a surgical window in the wall of the cyst, removing the contents and suturing the cyst wall to the surrounding epithelium
- encourages the cyst to decrease in size and may be followed up by enucleation at a later date
enucleation if the treatment of choice for most cysts, what are the advantages?
whole lining can be examined pathologically
primary closure
little aftercare needed
enucleation disadvantages
risk of mandible fracture with very large cysts
for dentigerous cyst - may wish to preserve tooth
old age/ill health
clot filled cavity may become infected
incomplete removal of lining may lead to recurrence
damage to adjacent structures
marsupialisation indications
if enucleation would damage surrounding structures
- e.g. ID nerve
difficult access to area
may allow eruption of teeth affected by dentigerous cyst
elderly or medically compromised patient
very large cysts would risk jaw fracture if enucleation was performed
marsupialisation advantages
simple to perform
may spare vital structures
can combine with enucleation at later procedure
marsupialisation disadvantages
opening may close and cyst may reform
complete lining not available for histology
difficult to keep clean
lots of aftercare needed
long time to fill in
function of an obturator in marsupialisation
used to keep marsupialisation window open
