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
- Among the most common lesions to affect the oral & maxillofacial regions.
- Gradually increase in size
Definition rules out abscesses (would be pus filled)
* If has pus inside – infected cyst e.g. cyst related to tooth, tooth becomes infected/get a sinus tract develop (supra-imposed infection)
Can differentiate between abscess and infected cyst on radiograph
Kramer, 1974
diveristy of cysts
very
Asymptomatic ↔ symptomatic
Slow growing ↔ fast growing
Indolent ↔ destructive
Almost all benign
HIGH INDEX of suspicion
slow growing swelling, pain, tenderness, tooth mobility or change in position, fail to erupt, discoloration of tooth.mucosa
high index of suscpicion for cysts
6
- 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
Signs & symptoms
* Often asymptomatic unless infected
Clinical progression as cyst pushes against bony cortices:
* bony swelling > “egg shell” crackling > fluctuant swelling
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 anatoomy
inclusion of unerupted teeth
assess location of abnormal lesion on radiograph
position in skeleton and relationship with tooth, canal etc
odotnogenic - tooth tissue origin
assess shape of abnormal lesion on radiograph
cysts often spherical or egg shaped
most grow by **hydrostatic pressure **
* tend to go path of least resistance - trabecular bone easier to spread in then outer cortical bone
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
3 Qs to ask when classifying cysts
structure
origin
pathogenesis
structure of cysts can be
epithelium lined Vs no epithelial lining
origin of cysts can be
odontogenic Vs non-odontogenic
pathogenesis of cysts can be
developmental Vs inflammatory
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
odontogenic cysts occur
Occur in tooth-bearing areas
(tooth materials – remnants of dental follicle, doesn’t need to be attached to tooth)
* rests of malassez
* rests of serres
* reduced enamel epith
most common cause of bony swelling in the jaw
odontogenic cysts
> 90% of all cysts in the oral & maxillofacial region2nd most common group of oral & maxillofacial lesions in adults (14-15%)
Most common are the mucosal pathologies
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
rests of malassex
remnants of herwig’s epithelial root sheath
rests of serres
remnants of the dental lamina
reduced enamel epithelium
remanants of the enamel organ
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
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
Can involve any tooth (but needs to be non vital)
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
spot the cyst and explain aetiology
No RCTx but due to crown prep may become unvital – overheating
Small but corticed margin so radicular cyst
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
1 key
3 others
- 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 (often incomplete – some areas hyperplastic and some missing)
Connective tissue capsule
Inflammation in capsule (dark blue dots are nuclei of inflammatory cells)
occ. see cholerterol clefts/mucous metaplasia and hyaline/rushton bodies
how can radicular cysts form from a periapical granuloma
explained histologically
Epithelial rests of Malassez proliferates in periapical granuloma - due to necrotic tissue from pulpal necrosis
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
unicentric growth cyst
balloon expansion with necrotic centre
buccal-lingual swelling
multicentric growht cyst
infiltrative growth
finger like prokection along length of bone
less clinical swelling
grow in antero-posterior direction
44yo female with hard swelling buccal to retained roots 35 & 36
“Egg shell” crackling upon palpation of the swelling
periapical taken - describe
Carious retained roots
Radiolucency
* Partly corticated
CBCT needed to further investigate
Interesting radiopacity superimposing 34
* Take a true occlusal to rule out submandibular salivary stone - was just an Artefact on film(not on CBCT)
describe CBCT findings
Unilocular, well defined, apical radiolucency
around carious RR so dx: radicular cyst
17yo male with soft swelling over apices of 12 & 13
Previous trauma to 12, 11, 21 & 22
describe PA
Radiolucency around 13 and 12 with well-defined margin
* cannot see full lesion on radiograph
* loss continuity of PDL
* non corticated
11 has a restored comp mesial-incisal edge
Degree of resorption around apex of 12
need OPT
discuss OPT findings
Unlikely to be cancer
the roots of teeth have moved (pt may complaint as crowding occurred),
large lesion breaching infraoribital foramen.
But limited as not 3D - need CBCT
discuss CBCT findings
Obliteration of RHS maxillary sinus and expanded into the nasal cavity (medial) see in coronal slice
Small radiolucency at apex of UL1, so possible multiple lesion or another pathology (seen in axial slice)
residual cyst
when radicular cyst persists after loss of tooth (or after tooth is succesfully RCTx)
knowledge of clinical/tx history important to avoid misdx
lateral radicular cyst
Radicular cyst associated with an accessory canal
Located at side of tooth instead of apex
inflammatory collateral cysts are
inflammatory odontogenic cysts
associated with a vital tooth
collective term for:
Paradental cyst
* Typically occurs at distal aspect of partially-erupted mandibular third molar
Buccal bifurcation cyst
* Typically occurs at buccal aspect of mandibular first molar
* Roots tilt lingually, crown tilts buccal
paradental cysts
inflammatory collateral/odontogenic cysts
occur at distal aspect of PE mandibular third molars typically
present with buccle behind 8
dentingerous cysts area
Developmental odontogenic cyst
Associated with crown of unerupted (& usually impacted) tooth
* e.g. mandibular third molars, maxillary canines
Cystic change of dental follicle
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 cemento-enamel junction of tooth
* Larger cysts may begin to envelope root of tooth - Be careful not to misinterpret
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
fluid between crown and reduced enamel epithelium?
Unsure why it happens
ATTACHED TO ACJ OF UNERUPTED TOOTH
41yo male complaining of “slight tenderness around back tooth”
No unusual clinical signs on examination other than over-eruption of last-standing molar
next step
Smaller PA not adequate – cannot see full extend of lesion get OPT
Unilocular, radiolucent associated with impacted LR8
highly likely dentingerous cyst
get CBCT to see extent of lesion
Compare between L and R to aid dx
dentingerous cyst Vs enlarged follicle
Consider cyst if follicular space >4mm
* Measure from surface of crown to edge of follicle
* Assume cyst if >10mm
Consider cyst if radiolucency is asymmetrical
gradual inc in size, damage to bone – need to remove
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
cause of eruption cysts
remains of serres
need to remve to allow tooth to erupt
only a small lesion around the crown of the tooth
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
Previously called keratocystic odontogenic tumour (until 2017)
**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)
histology of odontogenic keratocysts
Wall, epithelial lining, with cavity (semi solid filling)
Corrugated/wavey wall
*Straight barrier between epithelium and connective tissue – no rete pegs, easy to separate by mistake in surgery - recurrence *
PARAKERATINISEED unlike other cysts
Basal cells all the same height, nuclei at same level, picket fence appearance
Infection in wall of cyst can mean loss of characteristic keratocyst features
daughter cysts/cysts nests in wall – if not removed can cause recurrence
features of odontogenic keratocysts that make surgery difficult
thin friable lining - no rete pegs, wavey thin epithelium
has daughter cysts/nests in wall
recurrence high toot
describe why marsupilation surgery opted for this odontogenic keratocysts
and what happened
Highlight small size of cyst in first image
Risk damage to IAN and pathological fracture if trad surgery approach taken
Marsupialization – hole to encourage drain out
But recurrence still occurred – need to monitor for years after surgery
basal cell naevus syndrome
presentation
5
- Multiple odontogenic keratocysts
- Multiple basal cell carcinomas
- Palmar & plantar pitting
- Calcification of intracranial dura mater
etc.
a.k.a. Gorlin-Goltz syndrome; bifid rib syndrome
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
See bundle of nerves (spehnopalatine) 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
Mandible»_space; 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
May have scalloped margins giving a pseudolocular appearance
May project up between the roots of adjacent teeth –* finger like projection – strong indication, to monitor for 3-6months before surgery*
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 but commonly mistaken as one
Actually a depression in the bone
* Cortical bone preserved
Only occur in mandible, almost exclusively lingual
Contains salivary or fatty tissue (fills cavity)
presentation of stafne cavity
Most common in 5th & 6th decades
Often in angle or posterior body
Often inferior to inferior alveolar canal
Asymptomatic
Well-defined, often corticated radiolucency
Rarely displaces adjacent structure
dx
Very anxious 29yo male with swelling in cheek & bad taste
Clinical examination
* Swollen anterior face
* Draining sinus between teeth 22 & 23
* 22 & 23 slightly TTP
* 21 has longstanding RCT
odontogenic keratocyst in region 21, 22 and 23
need histology to confirm
enucleation - yellow/white substance is keratinous material (not pus)
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
