Cysts of the Jaws Flashcards
What is a cyst by definition?
A pathological cavity having fluid, semi-fluid or gaseous contents & which is not created by the accumulation of pus
Are cysts characteristically filled with pus?
NO
- only when cyst infected
What is usually the rate of progression of cysts?
Slow growing (but cyst dependant)
What are the common symptoms of odontogenic cysts?
- eggshell crackling (when pt presses area)
- mobility of adjacent teeth
- sensitivity of teeth in area
- absence of teeth in area
- numbness or neurological change
What special investigations may you do to investigate potential cystic lesions?
- take radiographs
- sensibility testing of adjacent teeth
What are some typical radiographic features of cysts?
- spherical or egg-shaped
- well defined margins
- corticated
- can be unilocular or multilocular
- may include unerupted teeth
How do most cysts grow generally?
by hydrostatic pressure
What effect on surrounding anatomy may cysts have that can be seen on radiographs?
Displacement of:
- cortical plates
- adjacent teeth
- maxillary sinus
- IAN canal
How could the locularity of this cyst be described?
Pseudolocular
What might cause a cyst to lose definition & cortication of margins?
Infection of cyst
What is the most common cause of bony swelling in the jaws?
Odontogenic cysts
- >90% of all cysts in the oral and maxfax region
How can the lining of odontogenic cysts be described?
Lined with epithelium
What are some odontogemic sources of epithelium?
- Rests of Malassez (remnants of Hertwig’s epithelial rooth sheath)
- Rests of Serres (remnants of the dental lamina)
- Reduced enamel epithelium (remnants of enamel organ)
Why might epithelium remnants become activated to form cysts?
- idiopathic
- infections
- cytokine infiltrations
What type of cysts can arise from the reduced enamel epithelium?
Dentigerous cyst
What are the most common odontogenic cysts?
- radicular cysts (60%)
- dentigerous cysts (18%)
- odontogenic keratocyst (12%)
What causes radicular cysts?
Initiated by chronic inflammation at apex of tooth due to pulp necrosis
- always associated with a non-vital tooth
What is the incidence of radicular cysts?
- most common in 4th&5th decades
- 60% maxilla: 40% mandible
- can involve any tooth
How do radicular cysts present?
- often asymptomatic (can become painful if infected)
- typically slow-growing with limited expansion
How do you tell between a periapical granuloma vs radicular cyst?
- radicular cysts typically larger (usually >15mm)
- radicular cysts typically have defined corticated margins on radiograph
- can only tell under microscope
What are the radiographic features of a radicular cyst?
- well defined, round/oval radiolucency
- corticated margin continuous with lamina dura of non-vital tooth
- larger lesions displace adjaecent structures
- long standing lesions may cause external root resorption &/or dystrophic calcification
What are the histological features of a radicular cyst?
- epithelial lining
- connective tissue capsule
- inflammation in capsule
(dark dots are inflammatory cells)
What cell types proliferate in periapical granulomas?
Epithelial rests of Malassez
What can radicular cysts form by?
- proliferating epithelium with central necrosis
- epithelium surrounds fluid area
How can the growth patten of radicular cysts be described?
Infiltration growth pattern
What is mucous metaplasia?
Epithelial cells become mucous secreting cells during cystic change
What is viewed here?
Hyaline/rushton bodies
What is viewed histologically here?
cholesterol clefts
What can cause numbness of IAN?
- infection
- trauma
- injury to nerve
- tumours
- cysts
What can cause radiopaque artifacts on receptors?
pressure from fingerprints
What are different variants of radicular cysts?
- residual cysts [when cyst persists after loss of tooth]
- lateral radicular cyst [radicular cyst associated with an accessory canal, located at side of tooth instead of apex]
What type of cyst is pictured here?
Residual radicular cyst
What type of cyst is pictured here?
Lateral radicular cyst
What are inflammatory collateral cysts?
Inflammatory odontogenic cysts
- associated with a vital tooth
What is a dentigerous cyst?
Developmental odontogenic cyst that is associated with the crown of unerupted [usually impacted] tooth
What are some symptoms of a dentigerous cyst?
- missing tooth
- swelling in area
What causes a dentigerous cyst?
cystic change of dental follicle
Where are radiolucent areas related to a dentigerous cyst seen?
around crown of the tooth extending to the ACJ
What are the radiographic signs of a dentigerous cyst?
- corticated margins attached to CEJ of tooth
- may displace involved tooth
- tend to be symmetrical initially
- variable displacement of cortical bone
How do dentigerous cysts present histologically?
- thin non-keratinised stratified squamous epithelium [may resemble radicular cyst if inflamed]
How do you decide between dentigerous cyst vs enlarged follicle?
Consider cyst if follicular space 5mm or more
- measure from surface of crown to edge of follicle
- assume cyst if >10mm
Also consider cyst if radiolucency is asymmetrical
How big is the normal follicular space?
2-3mm
How do you treat an eruption cyst?
- cut through cyst to allow tooth to erupt
What is the biggest problem associated with odontogenic keratocysts?
Recurrence!!!
What is a odontogenic keratocyst?
Developmental odontogenic cyst but NO specific relationship to teeth
What is the incidence of odontogenic keratocysts?
- most common in 2nd & 3rd decades
- male > female
- mandible > maxilla (3:1)
- posterior > anterior
How do odontogenic keratocysts present radiographically?
- often have scalloped margins
- 25% are multilocular
- often cause displacement of adjacent teeth
- enlarged markedly in medullary bone space BEFORE displacing cortical bone
What pre-operative diagnostic tests would you do to assess a potential OKC? What would this show?
Cyst aspirate
- contains squames
- low soluble protein content !
How do odontogenic keratocysts present histologically?
- epithelial lining WITH keratin formation [parakeratosis]
- basal palisading = nuclei are all at same level/height [uniform appearance]
- daughter cysts
- very thin friable lining so not attached very well to underlying tissue
What syndrome is associated with odontogenic keratocysts?
Basal cell naevus syndrome (Gorlin Goltz syndrome)
What is the presentation of Basal cell naevus syndrome?
- multiple odontogenic keratocysts
- multiple basal cell carcinomas
- palmar & plantar pitting
What are some examples of non-odontogenic cysts?
- nasopalatine duct cyst [most common]
- solitary bone cysts
- aneurysmal bone cyst
What is a nasopalatine duct cyst?
Developmental non-odontogenic cyst
- arises from nasopalatine duct epithelial remnants
- occurs in anterior maxilla
What is pictured here?
Nasopalatine duct cyst
How do nasopalatine duct cysts present?
- often asymptomatic
- patient may notice ‘salty’ discharge
- larger cysts may displace teeth or cause palatal swelling
- always involve midline but not always symmetrical
How does the histology of a nasopalatine duct cyst present?
variable epithelial lining
What are the radiographic findings of a nasopalatine duct cyst?
- corticated radiolucency between/over roots of cental incisors
- often unilocular
- “heart shaped”
How can you differentiate between a nasopalatine duct cyst vs the incisive fossa?
Consider the transverse diameter:
- <6mm: assume incisive fossa
- 6-10mm consider monitoring
- >10mm suspect cyst
What is a solitary bone cyst?
Non-odontogenic cyst WITHOUT an epithelial lining
- more common in mandible than maxilla
- occurs in teenagers [most common in 2nd decade]
How do solitary bone cysts present clinically?
- usually asymptomatic [tends to be an incidental finding]
- rarely pain or swelling
How do solitary bone cysts present radiographically?
- majority in premolar/molar region of mandible
- variable definition & cortication
- may have scalloped margins giving a pseudolocular appearance
- may project up between the roots of adjacent teeth?
How are solitary bone cysts managed?
These cysts go away on their own!
- always monitor incase you see any significant change
- ensure you don’t misdiagnose [could be a keratocyst]
What is a Stafne cavity?
NOT A CYST but commonly mistaken as one!
- depression in the bone of the mandible
- contains salivary or fatty tissue
Where do Stafne cavities typically lie?
- angle or posterior body of mandible
- often inferior to inferior alveolar canal
- asymptomatic
- well defined, often corticated radiolucency
How might we obtain material for histopathological analysis?
- Aspiration biopsy [drainage of contents]
- Incisional biopsy [partial removal]
- Excisional biopsy [complete removal]
What is used to undertake an aspiration biopsy?
- wide bore needle
- 5-10ml syringe
What can you get from an aspiration biopsy of a cyst?
- air
- blood
- pus
- cyst fluid
What cystic lesion can you aspirate blood from?
Aneurysmal cyst
How does cyst fluid of keratocysts typically present?
white or cream semi-solid fluid
What are the clinical steps of taking an incisional biopsy of a cyst?
- done under LA
- select place where lesion appear superficial
- raise mucoperiosteal flap
- remove bone as required
- incise & remove a section of lining
What are the surgical options for removal of cysts?
- Enucleation
- Marsupialisation
What is meant by enucleation surgery?
All of the cystic lesion is removed
What is meant by marsupialisation surgery?
- creation of surgical window in the wall of the cyst, removing contents of the cyst & suturing the cyst wall to surrounding epithelium
- encourages the cyst to decrease in size & may be followed by enucleation at a later date
What are the advantages of enucleation surgery of cysts?
- whole lining can be examined pathologically
- primary closure
- little aftercare needed
What are the contraindications/disadvantages of enucleation surgery of cysts?
- risk of mandibular fracture with very large cysts
- old age: ill health
- clot-filled cavity after surgery may become infected
- damage to adjacent structure
- incomplete removal of lining may lead to recurrence
When would marsupialisation surgery of a cyst be indicated?
- in enucleation would damage surrounding structures
- difficult access to area
- may allow eruption of teeth affected by a dentigerous cyst
- if enucleation would risk jaw fracture
- elderly or medically compromised pt unable to withstand extensive surgery
What are the advantages of marsupialisation?
- simple to perform
- may spare vital structures
What are the contraindications/disadvantages of marsupialisation of cysts?
- opening may close & cyst may reform
- complete lining not available for histology
- difficult to keep clean & lots of aftercare needed
- takes a long time to fill in
