cysts Flashcards
what is a cyst
pathological cavity filled with fluid, semi-fluid or gaseous contents not created due to the accumulation of pus
what are the odontogenic developmental cysts (3)
odontogenic keratocyst
dentigerous cyst (eruption)
lateral periodontal cyst
what are the inflammatory odontogenic cysts
radicular cyst (and residual)
inflammatory collateral cysts (paradental, buccal bifurcation)
name 3 non odontogenic cysts
nasopalatine duct cyst
solitary bone cyst
aneurysmal bone cyst
what are the odontogenic sources of epithelium and what cysts may arise from each
rests of mallasez - radicular
rests of serres - OKCs, lateral periodontal
reduced enamel epithelium - dentigerous and eruption
epidemiology of radicular cysts
- gender
- age
-location
M>F
30s and 40s
maxilla 60%, mandible 40% and can affect any tooth
process of radicular cyst formation
pulp necrosis
periapical periodontitis
periapical granuloma
radicular cyst
how may a radicular cyst present if it perforates the cortex
bluish, fluctuant submucosal swelling
radiographic presentation of radicular cyst
always associated with non vital tooth
well defined round/ oval radiolucency
corticated margins continuous with lamina dura of non vital tooth
large lesions may displace adjacent structures
what may be seen radiographically in long standing radicular cysts
external root resorption
dystrophic calcification
dystrophic calcification
deposition of calcium salts in tissues in the absence of systemic mineral imbalance
2 suggested methods of how radicular cysts form
proliferation of rests of mallasez within chronic periapical granuloma then
1. proliferating epithelium sees central necrosis as no blood flow leaving behind a cavity
2. epithelium proliferates to surround an area of fluid
how do radicular cysts grow
hydrostatic pressure - all parts of cyst increase in size at same rate and same time (ballooning)
contents of radicular cyst
watery straw coloured fluid - semi solid brownish material
name 3 histological features of epithelium that may be seen in radicular cysts
cholesterol clefts
mucous metaplasia
rushton bodies
mucous metaplasia
epithelial cells become mucous secreting cells
rushton bodies
(hyaline)
only present in odontogenic cysts
no diagnostic significance
produce unusual red substance
cholesterol clefts
when biopsy is processed, cholesterol is dissolved out leaving spaces known as cholesterol clefts
cholesterol is released when RBCs are broken down. deposits of haemosiderin are commonly associated (iron storage after RBC breakdown)
lateral radicular cyst
associated with accessory canal
located at side of tooth rather than apex
residual cyst
radicular cyst which persists after loss of tooth or after tooth has been root treated
inflammatory collateral cysts
inflammatory odontogenic cysts
associated with a vital tooth
collective term for paradental cyst and buccal bifurcation cyst
paradental cyst
distal aspect of partially erupted M3Ms
inflammatory stimulus often pericoronitis
well defined radiolucency related to neck of tooth and coronal third of root
buccal bifurcation cyst
typically occurs at buccal aspect of mandibular 1st molar
occurs in children
epidemiology of dentigerous cysts
- age
- gender
- location
- 10s-30s
-M>F - mandible >maxilla
dentigerous cyst
developmental odontogenic cyst
associated with crown of unerupted and usually impacted tooth
cystic change of dental follicle
radiographic presentation of dentigerous cyst
corticated margins attach to CEJ
tooth involved may be displaced a considerable distance
tend to be symmetrical initially but larger cysts may expand unilaterally
variable displacement of cortical bone
well defined unilocular radiolucency
what epithelium lines dentigerous cysts
thin layer of non keratinised squamous epithelium
what epithelium do dentigerous cysts arise from
reduced enamel epithelium
normal size of dental follicle
2-3mm
follicle vs cyst sizes
> 5mm consider cyst and monitor
10mm assume cyst
also consider cyst if radiolucency asymmetrical
eruption cyst
variation of dentigerous cyst associated with erupting tooth
contained within soft tissue rather than bone - bluish translucent soft swelling
most commonly incisors and almost exclusively seen in children
often requires no treatment
histology of eruption cyst
2 layers of epithelium -1 is gingiva, 1 is cyst epithelial lining
space between is connective tissue
epidemiology of OKC
- age
- gender
- location
10s-30s
M>F
mandible>maxila , posterior >anterior
radiographic presentation of OKCs
often scalloped margins
25% multilocular
often cause displacement of adjacent teeth
root resorption is uncommon
characteristic antero-posterior expansion> buccal lingual - can progress significantly before being noticed
why do OKCs have a high recurrence rate
thin linining
daughter cysts
multiloclular
pre op diagnostic test for OKC
cystic aspirate
OKC has characteristic low soluble protein content (<4g/decilitre)
what epithelium are OKCs lined with
stratified parakeratinised squamous epithelium
characteristic appearance of OKC basal cells
palasading appearance - nuclei all the same shape, size and at the same level (soldiers)
why does OKC epithelium often break away during removal
weak attachment to underlying connective tissue
no rete pegs
what epithelium do OKCs originate from
rests of serres
3 characteristic histological signs of OKCs
palasading
daughter cysts
parakeratinisation
basal cell naevus syndrome
inherited syndrome that sees multiple basal cell carcinomas
also multiple OKCs
lateral periodontal cyst
rare
associated with lateral surface of vital tooth root
gingival cysts
derived from rests of serres
adults: <1cm bluish/pink sessile swelling
infants: bohns nodules, small yellow/cream nodules on edentulous alveolar mucosa
nasopalatine duct cyst
developmental non odontogenic cyst arises from nasopalatine duct epithelial remnants
epidemiology of nasopalatine duct cysts
- gender
- age
- M>F
- 30s and 40s
symptoms of nasopalatine duct cyst
usually asymptomatic
patient may report salty discharge
larger cysts may displace teeth or cause palatal swelling
radiographic presentation of nasopalatine duct cyst
unilocular, well defined radiolucency with corticated margins
always involves midline but may not be symmetrical
may appear heart shaped due to superimposition of nasal spine
radiographs for nasopalatine duct cyst
PA and standard maxillary occlusal
histology of nasopalatine duct cyst
non keratinised squamous epithelium lining with modified respiratory
neurovascular bundles found within capsule
cyst vs incisive fossa sizes
in absence of other clinical issues
<6mm assume fossa
6-10mm consider cyst and monitor
>10mm suspect cyst
solitary bone cyst
non odontogenic cyst with no epithelial lining
epidemiology of solitary bone cyst
- age
- gender
- location
- teens
- M>F
- mandible >maxilla
radiographical findings of solitary bone cyst
pre molar/ molar region of mandible
variable definition and cortication
may project up between roots of adjacent teeth
stafne cavity
NOT a cyst
usually below IAC
indentation on lingual aspect of mandible
aspiration biopsy
done using a wide bore needle and 5-10ml syringe
can retrieve air, blood, pus and cyst fluid
incisional biopsy
done to obtain a sample of histopathological analysis
usually done under LA
may be combined wtih marsupialisation
process of incisional biopsy
select point where lesion appears superficial
raise mucoperiosteal flap
remove bone as required using round bur
incise and remove a section of lining
advantages of enucleation
- whole lining can be examined
- primary closure
- little aftercare
disadvantages of enucleation
- risk of mandibular fracture if very large cyst
- patient may wish to preserve associated tooth
- old/age ill health
- damage to adjacent structures
- incomplete removal of lining may lead to recurrence
indications for masupialisation
enucleation would damage adjacent structures
difficult to access to area
elederly or immunocompromised not able to withstand enucleation surgery
may allow eruption of associated teeth
can be combined with enucleation at later date
enucleation risks mandibular fracture
advantages of marsupialisation
easy to perform
may spare vital structures
how is marsupialisation window kept open
obturator
disadvantages of marsupialisation
opening may close and cyst may reform
complete lining not available for histology analysis
difficult to keep clean
lots of aftercare
treatment of nasopalatine duct cyst
enucleation
process of enucleation
- raise mucoperiosteal flap
- thin bone covering cyst is removed
- cyst lining separated from bony wall using curettes or periosteal elevators
- lining sent for histopathological analysis
- after irrigating with saline, flap sutured back in place
process of marsupialisation
- extract tooth or raise flap to expose cyst
- aspirate cyst contents then irrigate
- opening initially maintained with surgical pack then at a later date an obturator
- patient must irrigate cavity twice daily with saline
