Cysts Flashcards
What is a cyst?
A pathologial cavity having fluid , semi-fluid or gaseous contents and which is not created by the accumulation of pus
Signs and symptoms of cysts?
- mostly benign unless infected
What investigations to carry out for cysts?
initial
- periapical radiograph
- occlusal radiograaph
- Panoramic radiograph
supplemental
- cone beam CT (CBCT)
- Facial radiographs
- PA mandible
How are cysts classified?
Structure - epithelium lined : non epithelial lining
Origin : odontogenic : non-odontogenic
Pathogenesis : developmental vs inflammatory
Types of odontogenic developmental cysts?
- dentigerous cysts
- odontogenic keratocyst
- lateral periodontal cyst
Types of odontogenic inflammatory cysts
- radicular cyst and residual cyst
- inflammatory collateral cyst (paradental and buccal bifurcation cyst)
non odontogenic developmental cysts?
- nasopalatine duct cyst
non epithelial cysts
- solitary bone cyst
- aneurysmal bone cyst
What are odontogenic cysts?
They occur in tooth bearing areas
- most common cause of bony swelling in the jaws
- they are all lined with epithelium
Odontogenic sources of epithelium?
- Rests of malassez - remnants of hertwig’s epithelial root sheath
- Rests of serres - remants of the dental lamina
- Reduced enamel epithelium - remnants of the enamel organ
What are the most common odontogenic cysts?
- Radicular cysts (residual cyst) - 60%
- Dentigerous cysts (eruption cyst) - 18%
- Odontogenic keratocyst - 12%
What is a radicular cyst?
- it is an inflammatory odontogenic cyst
- associated with non vital tooth
- initiated by chronic inflammation at apex of tooth due to pulp necrosis
- mostly affecting maxilla
What is the presentation of a radicular cyst?
- asymptomatic unless indected
- slow growing with limited expansion
- radiolucency more than 15mm
What are the radiographic features of radicular cysts?
- well defined, round or oval radiolucency
- corticated margin continuous with lamina dura of non vital tooth
What might be the dental effects of radicular cysts?
- may cause displacement of adjacent structures
- may cause external root resorption
What is the histology of radicular cysts
- epithelial lining (often incomplete)
- connective tissue capsule
- inflammation in capsule
- originate from epithelial cells of malaasez
How due radicular cysts form?
- rests of malassez proliferate in periapical granuloma
- they can then form by proliferating epithelium with central necrosis or epithelium surrounds fluid area
What are the two growth mechanisms for radicular cysts ?
- Osmotic effect with semi-permeable wall
- Cytokine mediated growth
What are the histological features of radicular cysts?
- variable inflammation
- cholestrol clefts
- mucous metaplsia
- Hyaline/rushton bodies
How can you describe radicular cysts on palpation?
eggshell crackling
What are the two variants of radicular cysts?
- residual cyst : radicular cyst that persists after loss of tooth
- Lateral radicular cyst : associated with an accessory canal , located at side of tooth instead of apex
What is an inflammatory collateral cyst?
it is an inflammatory odontogenic cyst associated with a vital tooth
What are the types of inflammatory collateral cysts?
- paradental - distal aspect of partially erupted third molar
- Buccal bifurcation cyst - buccal aspect of mandibular first molar
What is dentigerous cyst
It is a developmental odontogenic cyst associated with a crown of unerupted ot impacted tooth (mandibular 8s or upper 3s)
- associated with cystic change of dental follicle
How are dentigerous cysts present radiographically?
- corticated margins attached to cemento-enamel junction of tooth
- may displace involved tooth
what is the histopathology of dentigerous cysts?
thin non keratinised stratified sqaumous epithelium
How to differentiate between dentigerous cyst and enlarged follicle?
- if follicular space is 5mm or more
- normal follicular space is 2-3mm
- if radiolucency is asymmetrical consider cyst
What is eruption cyst
- it is a variant of dentigerous cyst
- contained within soft tissue rather than bone
- associated with an erupting tooth (more commonly incisors and in children)
What is odontogenic keratocyst?
It is a developmental odontogenic cyst that is not associated with teeth
How does it grow?
- can enlarge in medullary bone
- can have significant mesio-distal expansion without bucco-lingual expansion
Histology of odonotogenic keratocyst
- Have cyst aspirate (low soluble protein content)
- Have parakeratosis
- basal palisading
- loss of keratin if inflammed
What is basal cell naevus syndrome?
- presents as multiple odontogenic keratocysts
- can have calcification
- known as gorlin-goltz syndrome
- associated with multiple basal cell carcinomas
Examples of non odontogenic cysts ?
nasopalatine duct cyst
solitary bone cyst
aneurysmal bone cyst
What is nasopalatine duct cyst
- it arises from nasopalatine duct epithelial remnants and occurs in anterior maxilla
- AKA incisive canal cyst
What is the presentation of nasopalatine duct cyst?
- it is often asymptomatic
- have salty discharge
- large cysts may displace teeth or cause swelling in palate
- always involve midline bit not always symmetrical
What is the histology of nasopalatine cyst?
- variable epithelial lining
- non keratinised startified squamous and modified respiratory
What further investigations for histology?
- Aspirational biopsy - drainage of contents
- Incisional biopsy - Partial removal
- Excisional biopsy - complete removal
What kind of fluid you might find when performing aspirational biopsy?
inflammatory or developmental
clear straw coloured fluid
keratocyst
white or cream semi-solid fluid indicated keratocyst
What is the purpose of incisional biopsy?
to obtain a sample of the lining for histological analysis
how to perform incisional biopsy?
Usually under LA
- select place where lesion appears superficial
- raise mucoperiosteal flap
- remove bone as required
- incise and remove a section of the lining
(this may be combined with marsupialisation)
What are the treatment options of cysts?
Enucleation
Marsupialisation
What is enucleation?
all of the cystic lesion is removed
What is marsupialisation?
- creation of a surgical window in the wall of the cyst, removing the content of the cysts and suturing the cyst wall to the surrounding epithelium
- encourages the cyst to decrease in size and may be followed by enucleation at a later date
What are the advantages of enucleation?
- whole lining can be examined pathologically
- primary closure
- little aftercare needed
What are the contraindicatoins and disadvantages of enucleation?
- risk of mandibular fracture
- may wish to preserve tooth for dentigerous cysts
- old in age
- incomplete removal of lining may lead to recurrance
- damage to adjacent structures
- Clott filled cavity may become infected
What are the indications of marsupialisation?
- if enucleation would damage adjacent structures
- difficult access to the area
- may allow eruption of teeth affected by a dentigerous cyst
- Elderly or medically compromised patients that cannot withstand complex 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 marsupialisation?
- simple to perform
- may spare vital structures
What are the contraindications of marsupialisation?
- opening may close and cyst ay reform
- complete lining not available for histology
- difficult to keep clean and lots of aftercare needed
- long time to fill in
