Cysts of the jaw Flashcards
defintition of a cyst
pathological cavity having fluid, semi-fluid or gaseous contents & which is not created by the accumulation of pus
- but can get infected and filled with pus
Kramer, 1974
Classification of Cyst from
WHO 2017 classification
diveristy of cysts
very
- Asymptomatic ↔ symptomatic
- Slow growing ↔ fast growing
- Indolent ↔ destructive
- Almost all benign
high index of suscpicion for cysts
5
- slow growing swelling
- pain / tenderness
- tooth mobility or change in position
- fail to erupt
- discoloration of tooth/mucosa
describe
Eruption cyst – fail to erupt, blue hue on mucosa
describe
Slight obliteration of mucobuccal fold, tender to pt, eggshell cracking
what to do here in first instance
Check vitality of tooth to see if related to tooth
If vital – unlikely to be involved, so periodontal cyst
clinical presentation of cyst ( S+S)
Signs & symptoms
- Often asymptomatic unless infected
/
- Tooth mobility
- loss of vitality - tooth
- discoloration of gingivae
- numbness
- Egg shell cracking ( bone thinning)
radiographic investigation of suspected cyst
order
Initial
- Periapical radiograph
- Occlusal radiograph
- Panoramic radiograph
Supplemental
- Cone beam CT (CBCT)
- Facial radiographs -PA mandible view; Occipitomental view
Choice dictated by pt history and clinical examination
radiographic features to use when assessing abnormal lesion on radiograph
7
location
shape
margins
locularity
multiplicity
effect on surrounding anatomy
inclusion of unerupted teeth
assess shape of abnormal lesion on radiograph
cysts often spherical or egg shaped
most grow by hydrostatic pressure
assess margins of abnormal lesion on radiograph
often well defined
often corticated
assess locularity of abnormal lesion on radiograph
cysts often unilocular
can be multilocular or pseudolocular
locules - balloons/compartments
assess multiplicity of abnormal lesion on radiograph
single, bilateral, multiple
multiple cysts may indicate syndrome
assess effect on surrounding anatomy of abnormal lesion on radiograph
displacement of cortical plates, adj teeth, maxillary sinus, inferior dental nerve canal
IDC pushed down
how to tell if cysts infected on radiograph
can lose defintion and cortication of margins if secondarily infected
typically associated with clinical signs/symptoms too
classifying cysts
3
structure
- epithelium lined
- no epithelial lining
origin
- odontogenic
- non-odontogenic
pathogenesis
- developmental
- inflmmatory
6 types of odonogenic cysts
developmental
- denigerous cyst (+eruption cysts)
- odontogenic keratocyst
- lateral periodontal cyst
inflammatory
- radicular cyst (+residual cyst)
- inflammatory collaterals
- paradental cyst or
- buccal bifurcation cysts
odontogenic inflammatory cysts result from
the proliferation of epithelium due to inflammation.
3 types of non-odontogenic cysts
developmental
- nasopalatine duct cyst
“Other” because their aetiology is still debated (no epith lining)
- solitary bone cyst
- aneurysmal bone cyst
all odontogenic cysts are
lined with epithelium
odontogenic sources of epithelium
3
Rests of Malassez
- Remnants of Hertwig’s epithelial root sheath
Rests of Serres
- Remnants of the dental lamina
Reduced enamel epithelium
- Remnants of the enamel organ
where does remnants of HERS stay
HERS break down after root formation, remnants remain inactive in PDL
(vital but dont divide)
most common odontogenic cysts
in order 1-3
- Radicular cyst (& residual cyst) 60%
- Dentigerous cyst (& eruption cysts) 18%
- Odontogenic keratocyst 12%
radicular cysts are
Inflammatory odontogenic cyst
Always associated with a non-vital tooth (attached, vitality test needed)
Initiated by chronic inflammation at apex of tooth due to pulp necrosis
incidence of radicular cysts
Most common in 4th & 5th decades - more chance of non-vital tooth
Male ≈ female
60% maxilla; 40% mandible
pathogensis of radicualr cyst
- pulpal necrosis
- periapical periodontitis
- periapical granuloma
- radicular cyst
presentation of radicular cyst
often asymp
may become infected - then have pain
typically slow growing with limited expansion
radicular cysts Vs periapical granulomas
Difficult to differentiate radiographically
Radicular cysts typically larger, smaller more likely to be periapical granuloma (save surgery)
If radiolucency diameter >15mm then 2/3’s of cases will be radicular cysts
radiographic features of radicular cyst
3 others
1 key
- Well-defined, round/oval radiolucency
- Corticated margin continuous with lamina dura of non-vital tooth
- Larger lesions may displace adjacent structures
- Long-standing lesions may cause external root resorption &/or contain dystrophic calcification
histological features of radicular cysts
3
- Epithelial lining - non keratinised squamous
- (often incomplete – some areas hyperplastic and some missing)
- Connective tissue capsule
- Inflammatory infiltrate
- (dark blue dots are nuclei of inflammatory cells)
- presence of Hyaline Bodies
- chloesterol clefts
- mucous metaplasia
occ. see cholerterol clefts/mucous metaplasia and hyaline/rushton bodies
radicular cyst content
- watery
- straw-colored fluid OR
- smei-solid brownish material
how can radicular cysts form from a periapical granuloma
explained histologically
Epithelial rests of Malassez proliferates in periapical granuloma
Radicular cysts may form by:
- Proliferating epithelium with central necrosis
- OR epithelium surrounds fluid area
Continued growth
- Osmotic effect with semi-permeable wall
- Cytokine mediated growth
pt c/o of ‘salty taste’ indicative of
infection of cyst
variants of radicular cyst
2
residual cyst
lateral radicular cyst - accessory canal
Residual: when radicular cyst persists after loss of tooth (or after tooth is succesfully RCTx)
radicular cyst tx
simple enucleation + removal of assoc tooth
inflammatory collateral cysts are
inflammatory odontogenic cysts
associated with a vital tooth
collective term for:
- Paradental cyst
- Buccal bifurcation cyst
paradental cysts
- inflammatory collateral/odontogenic cysts
- occur at distal aspect of PE mandibular third molars typically
- inflammatory stimulus - pericoronitis
present with buccle behind 8
dentingerous cysts
Developmental odontogenic cyst
Associated with crown of unerupted (& usually impacted) tooth
Cystic change of dental follicle
- e.g. mandibular third molars, maxillary canines
incidence of dentingerous cysts
Most common in 2nd-4th decades
Male > female
Mandible > maxilla (lower 3rd molars)
pt can complain of if dentingenerous cyst assoc with lower 8
salty taste if communication with oral cavity,
mobility of 7,
numbness as press on IDN
dentingerous cysts radiographic features
Corticated margins attached to CEJ of tooth
- Larger cysts may begin to envelope root of tooth
May displace involved tooth
Tend to be symmetrical initially
- larger cysts may begin to expand unilaterally
- variable bony expansion
histology of dentingerous cysts
2 key points
Thin non-keratinised stratified squamous epithelium
May resemble radicular cyst if inflamed
ATTACHED TO ACJ OF UNERUPTED TOOTH
dentingerous cyst Vs enlarged follicle
Consider cyst if follicular space >5mm
- Measure from surface of crown to edge of follicle
- Assume cyst if >10mm
Consider cyst if radiolucency is asymmetrical
eruption cyst
Variant of dentigerous cyst
- Contained within soft tissue rather than bone
Associated with an erupting tooth
- More commonly incisors
- Almost exclusive to children
blueish discoloration
odontogenic keratocysts are
Developmental odontogenic cyst
No specific relationship to teeth
- Tooth tissue origin but not related to tooth in particular
- formed from remains of dental lamina (likely)
incidence of odontogenic keratocyst
Most common in 2nd & 3rd decades
Male > female
Mandible > maxilla (3:1)
Posterior > anterior
Posterior body/ramus of mandible most common
High recurrence rate
common radiographic features of odontogenic keratocysts
5
- Often have scalloped margins
- 25% are multilocular
- Often cause displacement of adjacent teeth
- Root resorption uncommon
- Characteristic expansion
- Can enlarge markedly in medullary bone space before displacing cortical bone
- i.e. can have significant mesio-distal expansion without bucco-lingual expansion
late clinical presentation
pre-op dx tests for odontogenic keratocysts
cyst aspirate
- Contains squames
- Low soluble protein content
- <4g per deci litre (other cysts higher)
- thick, grey/ white cheesy material
histology of OKC
- PARAKERATINISED unlike other cysts - nuclei retained
- epithelium: thin, folded parakeratinised stratified squamous
- Basal palisading - nuclei at same level
- uninflamed
loss of keratin if inflamed
features of odontogenic keratocysts that make surgery difficult / high recurrence
- thin friable lining
- presnece of daughter cysts
- presence of cell nests
basal cell naevus syndrome
4
presentation
- Multiple OKC
- Multiple basal cell carcinomas
- Palmar & plantar pitting
- Calcification of intracranial dura mater
- Cysts histologically identical to non-syndromic form but often occur at a younger age (e.g. 15 years)
basal cell naevus a.k.a
2
Gorlin-Goltz syndrome;
bifid rib syndrome
multiple odontogenic keratocysts at a younger age (15yo)
nasopalatine duct cysts are
a.k.a. incisive canal cyst
Developmental non-odontogenic cyst
- Arises from nasopalatine duct epithelial remnants
- Occurs in anterior maxilla
Well defined radioluncecy where expect nasio-palatine duct
incidence of nasopalatine duct cysts
Most common in 4th-6th decades
M > F
presentation of nasopalatine duct cysts
- Often asymptomatic
- Patient may note “salty” discharge
- Larger cysts may displace teeth or cause swelling in palate
- Always involve midline but not always symmetrical
histology of nasopalatine duct cysts
- Variable epithelial lining
- Non-keratinised stratified squamous &
- modified respiratory
- cuboidal
- neurovascular bundles found in capsule
See bundle of nerves (sphenopalatine) and blood vessels – removed when cyst surgical removed - consent pt for numbess
radiography for nasopalatine duct cyst
Periapical &/or standard maxillary occlusal
- Corticated radiolucency between/over roots of central incisors
- Often unilocular
- May appear “heart shaped” due to superimposition of anterior nasal spine
Cone beam CT
- Indicated if better visualisation of cyst needed for surgical planning
nasopalatine duct cyst Vs incisive fossa
Incisive fossa
- May or may not be visible on radiographs
- Midline, oval-shaped radiolucency
- Typically not visibly corticated
In the absence of clinical issues, consider the transverse diameter
- <6mm: assume incisive fossa
- 6-10mm: consider monitoring
- >10mm: suspect cyst
solitary bone cysts are
Non-odontogenic cyst without an epithelial lining
a.k.a. simple/traumatic/haemorrhagic bone cyst
incidence of solitary bone cyst
Most common in 2nd decade
Male > female
Manidble > >maxilla
Can occur in association with other bone pathology
- e.g. fibro-osseous lesions
clinical presentation of solitary bone cysts
Usually asymptomatic - likely incidental finding
Rarely pain or swelling
Age – usually teens
radiographic appearance of solitary bone cysts
- Majority in premolar/molar region of mandible
- Can also occur in non-tooth-bearing areas
- Variable definition & cortication
- pseudolocular - scalloped margins
- finger like projection – btw the toothroots
most commonly found on OPT taken for orthodontic planning
solitary bone cysts management
monitor for 3-6 months
will usually manage itself within a year – no intervention needed
unlike keratocysts
stafne cavity is
- Not a cyst
- Actually a depression in the bone
- Cortical bone preserved
- Only in mandible, almost exclusively lingual
- Contains ectopic salivary tissue (fills cavity) in continuity with SMG
presentation of stafne cavity
Most common in 5th & 6th decades
Often in angle or posterior body
Often inferior to IAC
Asymptomatic
Well-defined, often corticated radiolucency
Rarely displaces adjacent structure
6 indications for masupialisation
- 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
adv of masupialisation
2
Simple to perform (LA)
May spare vital structures
contraindication/diadv of marsupilisation
4
- Opening may close & cyst may reform
- Complete lining not available for histology (may vary from small section taken)
- Difficult to keep clean & lots of aftercare needed – need pt cooperation, obturator needs to be in place to keep window open (syringe to irrigate)
- Long time to fill in – for up to 6 months
