Cysts of the jaws Flashcards
What is the pathogenesis of jaw cysts?
- source of epithelium
- stimulus for proliferation
- growth via osmotic factors and hydrostatic forces with unicentric expansion, eg. radicular cyst
- intrinsic properties of epithelial linings with multicentric expansion
- bone resorption via osteoclasts
What is the definition of a cyst?
Pathological fluid filled cavity lined by epithelium
Give some examples of odontogenic systs?
- radicular/residual (inflammatory)
- odontogenic keratocyst
- dentigerous cyst
- lateral periodontal cyst
- orthokeratinised keratocyst
What are some examples of non-odontogenic cysts?
- nasopalatine duct cyst
- nasolabial cyst
- branchial cyst
- dermoid cyst
- thryoglossal duct cyst
What are the symptoms of a cyst?
- swelling
- paraesthesia
- mobile teeth
- pain if infected
- bony expansion
- crepitus
- fluctuant swelling
- non-vital teeth
-displaced teeth
What radiographs can you take for cysts?
- plain films
- CBC gives an idea of the margin of the cavity
- CBCT gives an idea of contents of the cavity
What should the diagnosis of cysts be on?
Diagnosis must be on histological grounds.
Where do odontogenic cysts arise from and where do they affect?
they arise from tooth bearing epithelium
- rests of serres, REE, rests of malassez
- therefore only affect tooth bearing areas
What is a radicular cyst? Type?
An odontogenic cyst of inflammatory origin associated with a non-vital tooth.
- most common cysts of the jaws (55% of odontogenic cysts)
- peaks in 40-50 yrs
What is the pathogenesis of a radicular cyst?
Stimulation of the cell rests of malassez from apical inflammation secondary to pulpal necrosis
What is the histology of radicular cyst?
- lumen- layer of non-keratinised simple squamous epithelium
- surrounded by inflamed fibrous or granulation tissue
What is a residual cyst?
Remains after extraction of offending tooth
- predilection site- mandibular premolar area
What is a dentigerous cyst?
An odontogenic cyst that is attached to the cervical region of an unerupted tooth that envelopes the crown.
What is the pathogenesis of a dentigerous cyst?
Fluid accumulation between the reduced enamel epithelium and the crown of a tooth.
Which teeth are dentigerous cysts most commonly associated with?
Lower third molar
What is the presentation of a dentigerous cyst?
- symptomless, incidental finding
- painful if infected
- always attached to CEJ
What is the histology of a dentigerous cyst?
- lining- thin layer- 2 to 4 cells of regular epithelium
What is the lining of an odontogenic keratocyst?
- thin regular lining of parakeratinised stratified squamous epithelium
What cells are in the odontogenic keratocyst?
- palisading hyperchromatic basal cells
What does an odontogenic keratocyst come from?
- remnants of dental lamina
- cell rests of serres
Where are most odontogenic keratocysts found?
- 50% found in posterior body and ramus
What is the presentation of an odontogenic keratocyst?
- symptom free
- cause no expansion so often large at presentation
- can cause root displacement, but possibly resorption
What is the radiographic appearance of odontogenic keratocyst?
- multilocular, but unilocular is more common
- well defined
- usually corticated
What is the histology of an odontogenic keratocyst?
- thin regular parakeratinised epithelium which is thin, friabe and difficult to remove intact
- 5-8 cell layers thick
- without rete ridges
- parakeratin is usually corrugated- so keratin flakes can break off and fill cyst
- basal cell layer well defined, palisaded with hyperchromatic nuclei
- daughter cysts cause recurrence
What are the symptoms of Gorlin Goltz syndrome?
- multiple odontogenic keratocysts (mostly posterior maxilla)
- epidermoid carcinomas
- calcification of falx cerebri
- medduloblastoma
- frontal bossing
- bifid ribs
- nevoid basal cell carcinomas
What is a lateral periodontal cyst lined by?
Non-keratinised epithelium
Where does a lateral periodontal cyst occur?
- on the lateral aspect of tooth or between the roots of erupted teeth
- more in the mandible
What is the presentation of the lateral periodontal cyst?
- usually incidental finding
- tooth is vital
What is the radiographic finding of a lateral periodontal cyst?
- well defined
- corticated
- unilocular
- if multilocular- botryoid cyst
What does the nasopalatine duct cyst arise from?
- epithelial remnants in the incisive canal
What is the nasopalatine duct cyst lined with?
- respiratory type epithelium
What is the presentation of the nasopalatine duct cyst?
sessile swelling palatal to the maxillary incisors
- normal incisive canal is 6mm
What is the radiographic finding of nasopalatine duct cyst?
- well defined corticated lying between maxillary incisors and potentially displacing
- classically a heart shaped radiolucency
What is a solitary bone cyst?
An intraosseous cavity which is not lined by epitheliium and is either empty or filled with serous or sanguineous fluid.
- not a true cyst
Where is the solitary bone cyst mostly found?
- tooth bearing area
- usually body of mandible
What is the presentation of a solitary bone cyst?
- incidental finding
- radiograph shows scalloped and often extending between roots of teeth
- on opening up cavity it is usually empty, has no lining
- investigation is curative
What is the stafne defect due to?
Thought to be due to the submandibular gland pressing against lingual cortex.
What does the radiograph of stafne defect show?
Well defined, unilocular radiolucency in posterior mandible
- always below ID canal
What is an aneurysmal bone cyst?
Cystic or multi-cystic expansile osteolytic neoplasm composed of blood filled spaces separated by fibrous septa containing osteoclast like cells.
Which people does aneurysmal bone cyst occur in most?
- younger patients
- 10-20 years
What is the presentation of an aneurysmal bone cyst?
- painful bony swelling
- rapidly expanding
- unilocular or multilocular radiolucencies
How to decide what treatment to do for a jaw cyst?
- definitive histopathological diagnosis- sample
- biological behaviour of the lesion- nasty or nice
- location and dimension of the lesion- iatrogenic/pathological fracture
- proximity to important anatomical structures- neuropraxia
- patient compliance- enucleation vs marsupalisation- what will they manage what will they cope with
- other local factors like access
What is enucleation?
Complete removal of the whole cyst lining
What are indications for enucleation?
- accessible cysts not involving soft tissues
- small to moderately sized cysts not extensively involving vital teeth or important anatomical structures
What is the advantages of enucleation?
- complete removal of entire pathological tissue
- rapid healing
- decreased need for post operative care
Disadvantages of enucleation?
- large cysts are difficult to remove
- risk of damage
- risk of mandibular fracture
- risk of OAC or involvement of the nasal floor
- if the cyst extends to soft tissues, complete removal may not be possible and greater possibility of recurrence
How do you carry out enucleation?
curette is used to enucleate with the concave side towards the bone
- at the greatest diameter of the cyst, the curette is reversed facing the cyst lining
What is marsupialisation?
Cyst uncovered or de-roofed, maintained open so contents can drain out and the lining epithelium is exposed to the mouth.
What are the indications for marsupilisation?
- large cysts that are weakening the jaw
- cysts involving vital teeth
- cysts involving maxillary sinus or inferior alveolar canal
- dentigerous or eruption cysts to allow teeth to erupt
- in elderly patients
Disadvantages of marsupialisation?
- pathological tissue left
- get slow healing
- can get premature closure leading to further surgery
What are the advantages of marsupialisation?
- preservation of vital structures from surgical damage
- minimises bone removal
- bare bone not exposed to infection
- less traumatic than enucleation
- lining appears to become thicker and easier to enucleate histologically resembling oral mucosa
What surgery can you use adjunctively?
- peripheral ostectomy- remove peripheral bone
- en-bloc resection- including surrounding bone
What is cryotherapy?
Following enucleation, the bony cavity is frozen with cryoprobe (liquid nitrogen -70 degrees) for 1 minute, twice. If soft tissue involved, they are frozen for 30 seconds, twice.
How is Carnoy’s solution used?
As a fixative in conjunction with enucleation within the cystic cavity or bony cavity
- neurotoxic and carcinogenic
