Cysts of the Jaws 2 Flashcards
What is a nasal palatine duct cyst? (aka incisive canal cyst)
A developmental non-odontogenic cyst that arises from nasopalatine duct epithelial remnants
- Occurs in anterior maxilla
What are the epidemiological characteristics of NPD cysts?
Occurs in 40-60s
M>F
How do NPD cysts present?
- 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 (Grow off to one side)
How does the epithelial lining of NPD cyst vary?
Some areas are NK stratified squamous and some modified respiratory
Which radiographs are used to diagnose an NPD cyst?
PA
Standard maxillary occlusal
What are the radiographic features of an NPD cyst?
- Corticated radiolucency between/over roots of central incisors
- Often unilocular
- May appear “heart shaped” due to superimposition of anterior nasal spine
What are the radiographic features of the incisive fossa?
- May or may not be visible on radiographs
- Midline, oval-shaped radiolucency
- Typically not visibly corticated
How is incisive fossa distinguished from NPD cyst? (in absence of clinical issues)
If transverse diameter:
<6mm: assume incisive fossa
6-10mm: consider monitoring and take another x-ray in 6 months time
> 10mm: suspect cyst
What is a solitary bone cyst?
A Non-odontogenic cyst without an epithelial lining
What are the other names for solitary bone cyst?
simple/traumatic/haemorrhagic bone cyst
What are the epidemiological features of solitary bone cysts?
- Most common in 2nd decade
- Male > female
- Mandible > maxilla
- Can occur in association with other bone pathology e.g. fibro-osseous lesions
How are keratocysts distinguished from solitary bone cysts? Why is this important?
Bone cysts seen on younger patients with larger finger like projections in between
Important- keratocysts need to be managed
How do solitary bone cysts tend to present clinically?
Usually asymptomatic
-> incidental finding
Rarely- pain or swelling
What are the radiological features of a solitary bone cyst?
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 stafne cavity?
Not a cyst but commonly mistaken as one- Actually a depression in the bone (concavity)
-> Cortical bone preserved
-> Only occur in mandible, almost exclusively lingual
-> Contains salivary or fatty tissue
-> asymptomatic
When do stafne cavities tend to present?
50-60s
What are the radiographic features of a stafne cavity?
Location- angle or posterior body of mandible
-> often inferior to IDC
Well defined
Often corticated
Rarely displaces adjacent structures
What are the means of obtaining material from a cyst for histology?
- 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 is used for an aspiration biopsy?
Wide bore needle with 5-10ml syringe
What material may we get from an aspiration biopsy?
Air
Blood
Pus- infection
Cyst fluid
-> Clear straw coloured fluid in inflammatory or developmental cysts
-> White or cream semi-solid may indicate keratocyst
What can cause resistance in an aspiration biopsy?
Soft tissue blocking
What is the purpose of an incisional biopsy?
To obtain a sample of the lining for histological analysis
How is an incisional biopsy carried out?
Give LA
Select place where lesion appears superficial
Raise mucoperiosteal flap
Remove bone as required – using mongeurs or a round bur
Incise & remove a section of lining
What may an incisional biopsy be combined with?
Marsupialisation
What is the limitation of radiology in diagnosis of cysts?
Must follow up with histology for final diagnosis
What are the surgical treatment options for cysts?
Enucleation- treatment of choice most commonly
Marsupialisation
What is enucleation?
All of the cystic lesion is removed (entire cyst lining removed with the associated tooth/root if present)
What are the advantages of enucleation?
Whole lining can be examined pathologically
Primary closure
Little aftercare needed
What are the disadvantages of enucleation
- 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 is marsupilisation?
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
Done under LA
How is window kept open?
Obturator- prevents tissues growing back over it
What are the indications for marsupialisation?
- 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
What are the advantages of marsupialistion?
Simple to perform
Spares vital structures
What are the disadvantages of marsupialisation?
- 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
