Cysts of the Jaw Flashcards
What is a cyst?
A pathological cavity having fluid, semi-fluid or gaseous contents & which is not created by the accumulation of pus.
Allows it to gradually increase in size
What is the diagnosis if there is pus within the pathological cavity?
an infected cyst
what are the signs and symptoms of a cyst? (7)
often asymptomatic
most have mild symptoms:
- Swelling
Characteristic feature: slow growing swelling
- Pain & Tenderness
- Gradual tooth movements/spacing
- Mobility
- Prevented tooth eruption
- Discolouration of the tooth
How do you know if the cyst is coming from odontogenic origin or from the periodontium?
Assess the vitality
If vital = coming from the periodontium
What initial radiographs do you take if you suspect a cyst? (3)
Initial – start simple
* Periapical radiograph
* Occlusal radiograph (if larger)
* Panoramic radiograph (if very large lesion suspected)
- Don’t use for (esp upper) anterior cysts as anatomical features superimposed.
What follow-up radiographs do you take if you suspect a cyst? (4)
- Cone beam CT (CBCT)
others:
* Facial radiographs
* PA mandible view
* Occipitomental view
what important features must we assess if we suspect a cyst?
- Location
Has it risen for tooth tissues – situated in alveolar process
Odontogenic origin = location never above maxillary sinus or below IDN - Shape
- Often spherical or egg-shaped (Most grow by hydrostatic pressure) - Margins
- Often well defined
- Often corticated
Exception is when they are infected = lose definition - Locularity
- Often unilocular
- Can be multilocular (or pseudolocular - appears like this as it pushes up against other structures) - Multiplicity (how many of them are they)
- Single (common) , bilateral, multiple (usually because of a syndrome) - Inclusion of unerupted teeth
How do most cysts grow?
hydrostatic pressure
What is the most likely cause of a pathological lesion if the margins are undefined and it appears uncorticated?
infection (secondary)
- usually symptoms present
what 3 ways can you classify cysts?
structure - epithelium lined vs no ep lining
origin - odontogenic vs non-odontogenic
pathogenesis - developmental vs inflammatory
Where are odontogenic cysts present?
tooth-bearing areas
- as they arise from tooth material/teeth
What type of cysts are responsible for 90% of cysts in the oro-maxillofacial region?
Odontogenic cysts
Are all odontogenic cysts lined with epithelium?
yes
Briefly describe the 3 source of odontogenic cysts.
List the types of odontogenic cysts. (5)
What is the most common?
which one recurs the most?
Developmental:
Dentigerous cyst
(& eruption cysts)
Odontogenic keratocyst
(most commonly recurrs)
lateral periodontal cyst
Inflammatory:
Radicular cyst - most common
(& residual cyst)
inflammatory collateral cysts
What is a radicular cyst?
what are these always asosciated with
an Inflammatory odontogenic cyst
- Always associated with a non-vital tooth and always attached to a tooth
(if tooth vital = not this cyst)
- Initiated by chronic inflammation at apex of tooth due to pulp necrosis
Why do radicular cycts not COMMONLY occur in children/primary teeth? (2)
Teeth not in the mouth for long enough
Higher chance of dental disease in older patients
However can happen to any teeth that are non-vital – sensibility test to assess
In what jaw do radicular cysts most commonly present?
upper jaw
(in males more commonly than females)
How do radicular cycts present? (3)
- Often asymptomatic
- Cysts may become infected = pain
- Typically slow-growing with limited expansion
Describe how radicular cysts form.
Always associated with a non-vital tooth and always attached to a tooth
- Initiated by chronic inflammation at apex of tooth due to pulp necrosis
- pulpal necrosis then causes periapical periodontitis which then leads to the formation of a PA granuloma and then eventually a radicular cyst.
How do we tell the difference between a radicular cyst and a PA granuloma? (2)
Size:
Radicular cysts typically larger
- If radiolucency diameter >15mm = 2/3’s of cases will be radicular cysts
- Granuloma corrects after RCT, cyst may not
List the radiographic features of a radicular cyst. (4)
- Well-defined, round/oval radiolucency
- Corticated margin continuous with lamina dura of non-vital tooth
- Larger lesions may displace adjacent structures
- Long-standing lesions may cause external root resorption &/or contain dystrophic calcification
Name and describe briefly the 2 types of growth of cysts.
- Unicentric growth
- all parts expand at the same rate = unicentric ballooning of the cyst
- swelling = buccal lingual/palatal
- multicentric growth
- parts of epithelium more active = finger like processes = grow in an A/P direction along the length of the jaw bone = less clinical swelling
Name and describe variants of a radicular (inflammatory odontogenic) cysts.
residual cyst
- When radicular cyst (usually around apex of the NV tooth) persists after loss of tooth (or after tooth is successfully root canal treated)
- Encapsulated collection of fluid after the source of infection has been removed.
- Lateral radicular cyst
- Radicular cyst associated with anlateral/accessory canal (not the apex)
- Located at side of tooth instead of apex
What are inflammatory odontogenic collateral cysts?
List the types.
Inflammatory odontogenic cysts associated with a vital tooth
paradental cyst
buccal bifurcation cysts.
What is the main difference between a paradental cyst and a buccal bifurcation cyst?
Describe
They are the same type of cysts (Inflammatory odontogenic cysts associated with a vital tooth)
the difference is where they are occurring
- Paradental cyst - Typically occurs at distal (behind) aspect of partially-erupted mandibular third molar
- Buccal bifurcation cyst – Similar however typically occurs at buccal (buccal bifurcation) aspect of mandibular first molar
What is a dentigerous cyst?
what tooth are the most commonly associated with?
Developmental odontogenic cyst associated with crown of unerupted (& usually impacted) tooth
Cystic change of dental follicle
mandibular third molars,
In what jaw does dentigerous cysts most commony occur?
mandible
(males more than females)
List the radiographic signs of a dentigerous cyst. (6)
- Radiolucent with well-defined corticated margins which are attached to cemento-enamel junction of tooth (neck of the tooth)
- Has associated impacted lower right 3rd molar
- Larger cysts may begin to envelope root of tooth
- May displace the involved tooth
- Tend to be symmetrical initially - Larger cysts may begin to expand unilaterally
- Variable displacement of cortical bone (i.e. bony expansion)
What are the signs & symptoms of a dentigerous cyst? (2)
- mobility of the 7
- Lip is numb (cyst pushing on the IDN)
How can we tell the difference between a dentigerous cyst and an enlarged follicule? (3)
Histological Indicators of dentigerous cyst:
- Cuboidal epithelium
- Walls have islands of lamina
Clinical considerations:
Measure from surface of crown to edge of follicle
- Assume cyst if >10mm
- Consider cyst if radiolucency is asymmetrical
List a variant of a dentigerous cyst.
What are the differences between this and a dentigerous cyst. (3)
Eruption cyst.
- Contained within soft tissue rather than bone
- Associated with an erupting tooth (More commonly incisors)
- Almost exclusive to children
What is an odontogenic keratocyst?
A developmental odontogenic cyst - No specific relationship to teeth
may not be near/touching a tooth but arises from tooth tissue
What is the main way we differentiate a keratocyst from other odontogenic cysts?
may not be near/touching a tooth but arises from tooth tissue
In what jaw does a odontogenic keratocysts most commonly occur in?
mandible - esp posterior
(males more than females)
What are the radiographic & clinical characteristics of an odontogenic keratocyst? (5)
- Appears truly multilocular (don’t get multiocular radicular, dentigerous etc cysts) - 25% are.
- Often have scalloped margins
- associated Root resorption uncommon
- Often cause displacement of adjacent teeth
- High recurrence rate
Describe the characteristic expansion of a odontogenic keratocyst.
Can enlarge markedly in medullary bone space before displacing cortical bone
i.e. can have significant mesio-distal expansion without bucco-lingual expansion.
looks long like a sausage
What investigation do we carry out if we suspect an odontogenic keratocyst?
what are we testing for? (2)
aspirate biopsy
- Contains squames
- Low soluble protein content ( <4g per decilitre)
List 2 characteristics appearances of the histology of a keratocyst.
Palisading arrangement (basal cells at same height)
- If infection present = lose characteristic appearance
Daughter/satellite cysts found within the wall – if left behind they form a new keratocyst
Describe the type of growth keratocysts undergo.
Multicentric growth – parts of epithelial lining grows faster than other sites and have finger like projections (not a nice balloon shape)
- If projections left behind = reoccurrence
How do we exclusively treat keratocysts and why.
marsupialisation:
1. Cut a hole and allow it to drain slightly = reduces in size and moves away from the canal and reduces risk of mandibular fracture and can be removed easier.
- Remove tooth/source too to prevent recurrence
- Close monitoring for years post surgery
What syndrome is associated with multiple keratocysts?
Basal cell naevus syndrome:
How does Basal cell naevus syndrome present? (4)
- Multiple odontogenic keratocysts
- Multiple basal cell carcinomas
- Palmar & plantar pitting
- Calcification of intracranial dura mater
List non-odontogenic cysts. (4)
Developmental
nasopalatine duct cysts
other:
solitary bone cysts
aneurysmal bone cysts
What is a nasopalatine duct cyst?
where does it occur?
A developmental non-odontogenic cyst that arises from nasopalatine duct epithelial remnants
- Occurs in anterior maxilla
how does a nasopalatine duct cyst present? (3)
- Often asymptomatic
- Patient may note “salty” discharge (similar to infection)
- Larger cysts may displace teeth or cause swelling in palate
- Always involve midline but not always symmetrical (can grow off to one side)
Describe the epithelium lining the nasopalatine duct cyst. (2)
Variable epithelial lining;
- Non-keratinised stratified squamous
- modified respiratory
what radiographs do we use to image nasopalatine duct cysts? (2)
Periapical &/or standard maxillary occlusal
what are the radiographic features if a nasopalatine duct cyst? (3)
- Corticated radiolucency between/over roots of central incisors
- Often unilocular
- May appear “heart shaped” due to superimposition of anterior nasal spine
What radiographic feature can be used for diagnosis of a nasopalatine duct cysts in the absence of clinical signs/symptoms?
consider the transverse diameter;
* <6mm: assume incisive fossa
* 6-10mm: consider monitoring and take another x-ray in 6 months time
* >10mm: suspect cyst
In what patient do solitary bone cysts (non-odontogenic non-epithelial lined cyst) occur?
young adults/teenagers
what is a solitary bone cyst?
A Non-odontogenic cyst without an epithelial lining
a.k.a. simple/traumatic/haemorrhagic bone cyst
in what jaw do solitary bone cysts commonly occur in?
mandible ++
males more than females
How do we differentiate a solitary bone cyst and a keratocyst? (2)
SBC:
- Age (younger px)
- Larger finger like projections in-between teeth
What are the radiographic signs of a solitary bone cyst? (4)
- Majority in premolar/molar region of mandible - Can also occur in non-tooth-bearing areas
- Variable definition & cortication
- May have scalloped margins giving a pseudolocular appearance
- May project up between the roots of adjacent teeth
What is a Staphne cavity?
Not a cyst but commonly mistaken as one, is actually a depression in the bone (Cortical bone preserved)
can have an Ingrowth of salivary or fatty tissue
What are the characteristics of a staphne cavity. (5)
- Often in angle or posterior body
- Often inferior to inferior alveolar canal
- Asymptomatic
- Well-defined, often corticated radiolucency
- Rarely displaced adjacent structures
How can we further investigate cysts of the jaw? (3)
- Aspiration biopsy – drainage of contents
- Can do in GDP
- Can tell you if it’s a cavity or mass - Incisional biopsy – partial removal
- Can help differential diagnosis of ameloblastoma - Excisional biopsy – complete removal
What kind of fluid is collected from an inflammatory/developmental cyst during aspirational biopsy?
clear/straw coloured fluid
What kind of fluid is collected from a keratocyst during aspirational biopsy?
White or cream semi-solid
What is the purpose of an incisional biopsy?
To obtain a sample of the lining for histological analysis
List and describe the 2 treatment options for cysts.
enucleation
All of the cystic lesion is removed (entire cyst lining removed with the associated tooth/root if present)
- Treatment of choice for most cysts
marsupialisation (less invasive and can be done under LA however Requires cooperation)
- Creation of a surgical window in the wall of the cyst, removing the contents of the cyst & suturing the cyst wall to the surrounding epithelium
- Encourages the cyst to decrease in size & may be followed by enucleation at a later date
- Always a window present with something inside for up to 6 months e.g. an obturator to prevent tissues growing back over it
What are the advantages of enucleation? (3)
- Whole lining can be examined pathologically
- Primary closure
- Little aftercare needed
What are the disadvantages/contraindications of enucleation? (7)
- Risk of mandibular fracture with very large cysts
- (Dentigerous cyst) wish to preserve tooth
- Old age/ill health can’t be put under GA
- Clot-filled cavity may become infected
- Incomplete removal of lining may lead to recurrence
- Damage to adjacent structures
- Daughter cysts in the keratocyst lining – to remove all of these would cause damage to adjacent structures/anatomy = have to use marsupialisation
What are the advantages of marsupialisation? (2)
- Simple to perform
- May spare vital structures
What are the disadvantages/contraindications of marsupialisation? (4)
- Opening may close & cyst may reform
- Complete lining not available for histology
- Difficult to keep clean & lots of aftercare needed
- Long time to fill in
what are the indications for marsupialisation? (7)
- If enucleation would damage surrounding structures (e.g. ID canal)
- Difficult access to the area
- May allow eruption of teeth affected by a dentigerous cyst
- Elderly or medically compromised patients unable to withstand extensive surgery
- Very large cysts which would risk jaw fracture if enucleation was performed
- Can combine with enucleation as a later procedure
