Oral histopathology with cysts Flashcards
What is a cyst?
Pathological cavity having fluid, semi-fluid or gaseous contents and which is not created by accumulation of pus (pus can occur once cyst becomes infected).
Can be wholly or partly lined by epithelium
Give some examples of inflammatory cysts?
Radicular
Residual
Inflammatory collateral cysts - paradental, mandibular buccal bifurcation
Examples of developmental cysts
Dentigerous cyst
Odontogenic keratocyst
Gingival cysts
Explain aetiology of radicular cyst
ALWAYS associated with NECROTIC pulp - intiated by chronic inflammation apical PDL
Proliferation of RESTS OF MALLASEZ from Hertwig’s epithelial root sheath
What is a residual cyst?
Remnants of radicular cyst that remain after exctraction of affected tooth
Can get lateral residual cysts associated with accessory canal
Where is a radicular cyst most common?
Maxillary lateral incisors
How might a radicular cyst present clinically?
Often asymptomatic so incidental finding
Typically slow-growing and limited expansion
Might get “egg shell” crackling upon palpation of the swelling
Mobility of teeth
Discolouration of gingivae/ teeth
How does a radicular cyst present histologically
Incomplete epithelial lining
Connective tissue capsule - can have inflammation in this
Rests of malassez
Cholesterol clefts
Mucous metaplasia
Hyaline/ rushton bodies
How do radicular cysts form?
Periapical periodontitis to periapical granuloma - when it gets >15mm = radicular cyst
Proliferating epihtelium with central necrosis
OR
Epithelium surrounds fluid area
Where do paradental cysts typically occur and what type of cyst is it?
Typically distal aspect of partiall-erupted mandibular third molar
Inflammatory collateral cyst
Where do buccal bifurcation cysts occur and what type of cyst is it?
Typically occur at buccal aspect of mandibular first molar
Odontogenic inflammatory collateral cyst
What type of cyst is a dentigerous cyst and what is the aetiology?
Developmental odontogenic cyst
Associated with crown of unerupted (usually impacted) tooth - M3M and maxillary canines
Cystic changes of the dental follicle
Radiological signs of dentigerous cysts?
Corticated margins attached to CEJ of tooth
May displace involved tooth
Well-defined unilocular
Attached to crown of unerupted tooth
Typically symmetrical - larger cysts may begin to expand unilaterally
Histology of dentigerous cyst?
Thin, non-keratinised stratified squamous epithelium
Flat basement membrane
May resemble radicular cyst of inflamed
Non-cystic radiolucent lesions differential diagnosis
Odontogenic tumours - ameloblastoma, ameloblastic fibroma
Giant cell lesions - peripheral/ central giant cell granuloma
Fibro-cemento osseous lesions
Radiolucnet non-odontogenic tumours - squamous cell carcinoma, haemangioma
What type of cyst is odontogenic keratocyst and the aetiology/ features?
Developmental odontogenic cyst
Arises from REST OF SERRES - remnants of the dental lamina
Unusual growth pattern with high risk of recurrence
What is the growth pattern for odontogenic keratocyst?
Unusual - anterior-posterior direction
Can reach large size without causing gross bony expansion
What is an odontogenic keratocyst (OKC) and incidence?
Developmental odontogenic cyst - no specific relationship to teeth
Most common 2nd and 3rd decade
M>f
Mandible over maxilla
Posterior>anteiror
Histology OKC
Thin friable lining
Parakeratosis
Daughter cysts
Loss of keratin if inflamed
General management of cysts?
Referral
Initial consultation
Special investigation - plain film radiograph/ CBCT
Biopsy
Diagnosis
Treatment plan and discussion
Treatment options
- Enucleation
- Marsupialisation
- Surgical resection
What is cyst enucleation?
Removal of entire cyst lining and contents
Depends on size of cyst and type
What is cyst enucleation most useful for treating?
Radicular
Residual
Dentigerous
Keratocysts
NOT FOR AMELOBLASTOMA
Complications of cyst enucleation?
Mainly related to size, position and type of cyst
Damage to IAN
Communication with maxillary sinus OAC
Pathological fracture of mandible
Risk of recurrence
What is purpose of marsupialisation?
Creating a window in the cyst to allow for decompression of pressure and subsequent reduction in size for enucleation
Complications of marsupialisation?
Needs further surgery for removal cyst
Long treatment before completion
Chance of re-infection
Uncomfortable
May close over if no grommit
What is segmental resection of a cyst and what are they mainly used for?
Removal of cyst with margin of normal bone
Mainly used for ameloblastoma and sarcoma
Treatment for radicular cyst?
RCT the affected cyst if small
Can then consider peri-radicular surgery to remove cyst
OR
Extract necrotic tooth and see if cyst shrinks
If cyst becomes larger/ does not go away, enucleate
Give an example of an epithelial, non-odontogenic cyst?
Nasopalatine cyst
Note - originates from epithelial remnants of naso-palatine duct
What are the radiological features of a naso-palatine cyst?
Well-defined round, ovoid or HEART-shaped radiolucency
Sclerotic margin
Histopathology of a nasopalatine cyst
Lined by stratified squamous & respiratory or cuboidal epithelium
Neurovascular bundles found in capsule
Clinical features of a nasopalatine cyst?
M>F
5th and 6th decade
May be asymptomatic
Slowly enlarging swelling anterior region midline of palate
Radiological signs OKC
Scalloped margins
Oval
Uni/ multi-locular - most are multi-locular
Well-defined uniform radiolucency
