7 - Cysts of the jaw Flashcards
Define a cyst.
Pathological cavity having fluid, semi-fluid or gaseous contents and which is not created by the accumulation of pus (not infection or malignant by origin)
What are common symptoms that present with cysts?
- mobility of teeth
- swelling
- discolouration of superficial areas
- pain
- sensitivity
- numbness
- “egg shell crackling”
- often asymptomatic unless infected
What imaging can be used for initial assessment of cysts?
- PA
- occlusal
- OPT
What imaging can be used for supplemental assessment of cysts?
- CBCT
- facial radiographs (PA mandible/OM view)
How do most cysts grow?
Hydrostatic pressure
How do cysts with secondary infection present on a radiograph?
- loss of definition and corticated margin
- appear like malignancy
Define pseudolocular.
Scalloped edges without septae within (otherwise multilocular)
How can cysts be classified?
- structure (epithelium or not)
- origin (odontogenic or not)
- pathogenesis (developmental or inflammatory)
What is an odontogenic cyst?
- occurs in tooth bearing area
- most common cause of bony swelling in jaw
- lined with epithelium
- all found above IAN
What are odontogenic sources of epithelium?
- rests of malassez
- rests of serres
- reduced enamel epithelium
What are rests of malassez?
- remnants of Hertwig’s epithelium root sheath
- can be found in PDL dormant
- can be activated by infection
What are rests of serres?
Remnants of dental lamina
What is the reduced enamel epithelium?
- remnants of enamel organ
- covers crown before eruption
- commonly produces dentigerous cysts
What are the common odontogenic cysts?
- radicular
- dentigerous
- odontogenic keratocyst
What is a radicular cyst?
- inflammatory odontogenic cyst
- always associated with non-vital tooth
- initiated by chronic inflammation at apex of tooth due to pulp necrosis
What is the incidence of radicular cysts?
- 30-40 years
- M=F
- 60% maxilla
- any tooth
Describe the presentation of a radicular cyst.
- asymptomatic
- if infected, pain
- slow growing with limited expansion
Describe the difference between radicular cysts and periapical granulomas.
- periapical granuloma is a precursor to a radicular cyst
- if >15mm diameter on radiograph, consider a radicular cyst
Describe the radiographic features of a radicular cyst.
- well defined and corticated margins
- round, oval radiolucency
- corticated margin is continuous with lamina dura of a non-vital tooth
- long term cyst can cause displacement or root resorption
Describe the histology of a radicular cyst.
- epithelial lining is often incomplete
- connective tissue capsule
- inflammation within capsule
- cholesterol clefts present
How does a radicular cyst develop from a granuloma?
- cytokines stimulate rests of malassez to proliferate
- draws fluid in and expands
- interleukins stimulate osteoclasts to destroy local bone
What are the variants of radicular cysts?
- residual cyst (when tooth XLA)
- lateral radicular cyst (associated with accessory canal)
What is a inflammatory collateral cyst?
- inflammatory odontogenic cyst
- associated with vital tooth
- collective term for paradental and buccal bifurcation cysts
What is a paradental cyst?
Occurs at distal aspect of partially-erupted M3M
What is a buccal bifurcation cyst?
Occurs at buccal aspect of M1M
What is a dentigerous cyst?
- developmental odontogenic cyst
- associated with crown of unerupted (± impacted) tooth
- cystic change of dental follicle
What is the incidence of dentigerous cysts?
- 10-30 years
- M>F
- mandible>maxilla
Describe the radiographic appearance of a dentigerous cyst.
- corticated margins which attach at the CEJ
- larger cysts can envelop root of tooth
- usually symmetrical
- can displace involved tooth
Describe the histology of dentigerous cysts.
- thin non-keratinsed stratified squamous epithelium
- develops from reduced enamel epithelium and fluid accumulates
How do you differentiate between a dentigerous cyst and an enlarged follicle?
- consider cyst if follicular space >5mm (crown to margin)
- normal follicular space is 2-3mm
- consider cyst if radiolucency asymmetrical
What is an eruption cyst?
- variant of dentigerous cyst found in children
- contained in soft tissue rather than bone
- associated with erupting tooth (commonly incisors)
What is the management of an eruption cyst?
- incise
- allow tooth to erupt
What is an odontogenic keratocyst?
- developmental odontogenic cyst
- no specific relationship to teeth
- recurrence very common
- aka OKC
What is the incidence of OKC?
- 10-20 years
- M>F
- mandible>maxilla 3:1
- posterior>anterior
Describe the radiographic appearance of OKC.
- scalloping margins with thin lining
- 25% multilocular
- displacement of adjacent teeth (resorption uncommon)
- expansion through medullary bone (antero-posterior) before displacing cortical bone (bucco-lingual)
What are the pre-operative diagnostic tests for OKC?
- cyst aspirate
- low soluble protein
- OKC <4
- other cysts >11
Describe the histology of OKC.
- parakeratosis
- basal palisading (nuclei at same level like soldiers)
- corrugated lining
- no rete pegs so lining easily torn
Why is recurrence common in OKC?
- thin friable lining often tears in surgery
- daughter cysts present
- cell nests (retromolar area)
What systemic condition is associated with OKC?
- basal cell naevus syndrome
- aka Gorlin-Goltz syndrome
What is basal cell naevus syndrome?
- aka Gorlin-Goltz syndrome
- multiple OKC
- multiple basal cell carcinomas
- pitting on hands and feet
- calcification of dura mater
What are common non-odontogenic cysts found in max-fac?
- nasopalatine duct cyst
- solitary bone cyst
- aneurysmal bone cyst
What is a nasopalatine duct cyst?
- developmental non-odontogenic cyst
- arises from nasopalatine duct epithelial remnants
- occurs in anterior maxilla
Describe the incidence of nasopalatine duct cysts.
- 30-50 years
- M>F
Describe the radiographic appearance of nasopalatine duct cyst.
- corticated radiolucency between or over roots of central incisors
- unilocular
- can appear heart shaped
- always involve the midline but can be asymmetrical
Describe the presentation of nasopalatine duct cyst.
- asymptomatic (incidental finding)
- patient may note salty taste
- large cyst can displace teeth or cause swelling in palate
Describe the histology of a nasopalatine duct cyst.
- variable epithelial lining
- nonkeratinised stratified squamous
- modified respiratory
How do you differentiate between a nasopalatine duct cyst and the incisive fossa?
- incisive fossa present as a midline, oval shaped radiolucency, not corticated
- measure transverse diameter
- <6mm assumes incisive fossa
- > 10mm assumes cyst
- between should be monitored
What is a solitary bone cyst?
- non-odontogenic cyst without epithelial lining
- aka simple/traumatic/haemorrhagic bone cyst
- can occur in association with other bone pathology eg fibro-osseous lesions
What is the incidence of a solitary bone cyst?
- teenagers
- M>F
- mandible>maxilla
Describe the clinical presentation of a solitary bone cyst.
- asymptomatic (incidental finding)
- rarely associated with pain or swelling and usually resolve on their own
Describe the radiographic appearance of a solitary bone cyst.
- premolar/molar region of mandible
- can occur in non-tooth bearing areas
- variable in definition and cortication
- can have scalloped edges and may protect between roots of teeth
What is a Stafne cavity?
- not a cyst but commonly mistaken for one
- depression in bone (cortical bone preserved)
- occurs in mandible
- contains salivary or fatty tissue
Describe the radiographic appearance of a Stafne cavity.
- well defined, corticated radiolucency
- inferior to IAN
- rarely displaces adjacent structures
What does clear straw coloured fluid from an aspiration biopsy indicate?
- inflammatory or developmental cysts
- may “sparkle” from cholesterol clefts
What does white/creamy semi solid fluid from an aspiration biopsy indicate?
- OKC
- keratin present
If you cannot withdraw plunger in an aspiration biopsy, what does this mean?
Lesion is solid ie tumour
What type of cyst requires an incisional biopsy?
OKC
What are the treatment options for cysts?
- enucleation
- marsupialisation
What is enucleation?
All of cystic lesion is removed in one (lining fully removed)
What is marsupialisation?
- creation of surgical window in wall of cyst to create negative pressure
- walls of cyst are sutured to surrounding epithelium
- allows cyst contents to drain and cyst decrease in size
- should be followed by enucleation at later date as not ultimate treatment
What are the advantages of enucleation?
- whole lining can be examined by pathology
- primary closure
- little aftercare
What are the disadvantages of enucleation?
- risk of mandibular fracture in large cysts
- incomplete removal can lead to recurrence
- damage to adjacent structures
- clot filled cavity can become infected
What are the indications for marsupialisation?
- possible damage to adjacents structures
- difficult access
- may allow eruption of adjacent teeth
- elderly or medically compromised patients
- large cysts in which mandibular fracture is a risk
What are the advantages of marsupialisation?
- simple to perform
- may spare vital structures
What are the disadvantages of marsupialisation?
- opening may close and cyst reforms
- complete lining not available for pathology
- difficult to keep clean and extensive aftercare
- take a long time to fill in
What is used to ensure the surgical window in marsupialisation stays open?
Obturator
What follow up is require for OKC?
- at least 10 years
- CBCT
