Cysts of Jaws Flashcards
What is a cyst?
- Pathological cavity having fluid, semi-fluid or gaseous contents , not created by accumulation of pus
What are the key features of cysts that can be used to describe a cystic lesion?
Asymptomatic or symptomatic
Slow growing or fast growing
Indolent (lazy) or destructive
Almost all are benign
What radiographic investigations can be utilised in cystic diagnoses?
Initial
- PA
- Occlusal radiograph
- Panoramic
Supplemental
- Cone beam CT
- Facial radio like PA mandible view, occipitomental view
Give some Clinical features of cystic lesions
- Discolouration superficial area
- Loss of vitality and mobility of ass teeth
- May be hard at first then soft to touch (egg shell crackling) *** key to cystic lesion
- Usually slow growing
Describe this picture
- Blueish colour
- Swelling
- Absence of 21
Describe this lesion
- Dark Discolouration on labial surface of gingivae between 31 and 32
- Swelling
When you are describing a cystic lesion from a radiograph what must you include? (7)
- Location
- Shape (often spherical or egg shaped)
- Margins (Often well defined and corticated)
- Locularity (Often unilocular but can be multilocular or pseudolocular)
- Multiplicity (single, bilateral or multiple)
- Effect on surrounding anatomy (displacement of cortical plates, adjacent teeth, max sinus, IANC - variable degree and pattern of growth - root resorption from chronic)
- Inclusion of unerupted teeth
What can multiple cysts indicate?
- A syndrome
if a cyst is secondarily infected what can this change about appearance?
- Lose definition
- Los cortication of margins
- Ass with clinical signs and symptoms
What are the 3 categories that cysts can be classified into?
Structure
- Epithelium lined vs no epithelial lining
Origin
- odontogenic vs non-odontogenic
Pathogenesis
- Developmental vs inflammatory
If a cysts if odontogenic in nature it can be developmental or inflammatory. Give developmental cysts and give Inflammatory cysts
Developmental
- Dentigerous cyst (eruption cyst)
- Odontogenic keratocyte
- Lateral periodontal cyst
Inflammatory
- Radicular cyst (residual cyst)
- Inflammatory collateral cysts either Paradental cyst or Buccal bifurcation cyst
Give non-odontogenic cysts
Developmental
- Nasopalatine duct cyst
Other
- Solitary bone cyst
- Aneurysmal bone cyst
(both other have no epithelial lining)
Give the odontogenic sources of epithelium
Rests of Malassez
- Remnants of Hertwig’s epithelial root sheath
Rests of Serres
- Remnants of dental lamina
Reduced enamel epithelium
- Remnants of enamel organ
Give the epidemiology and incidence of odontogenic cysts
- Occur in tooth bearing areas
- All lined with epithelium
- Most common cause of bony swelling in jaws
- > 90% of all cysts in oral and maxillofacial region
Give the 3 most common odontogenic cysts and their prevalence
- Radicular cyst (residual cyst) approx 60% of odontogenic cysts
- Dentigerous cyst (eruption cyst)
approx 18% - Odontogenic Keratocyst
approx 12% in maxillofacial region
What is a radicular cyst? How do they occur?
- Inflammatory odontogenic cyst
- Always ass with non-vital tooth
- Initiated by chronic inflammation at apex of tooth due to pulp necrosis
What is the incidence of radicular cysts?
Most common 40/50
Equal in male and female
60% maxilla 40% mandible
Can involve any tooth
What is the presentation of radicular cyst?
- Often asymptomatic but when it is infected can cause pain
- Slow growing with lim expansion
Give the stages of non vital tooth becoming a radicular cyst
- Non vital tooth
- Pulpal necrosis
- Periapical periodontitis
- Periapical granuloma
- Radicular cysts
Give the difference of radicular cysts to periapical granulomas
- hard to differentiate radiographically but
- Radicular cysts larger so
if radiolucency >15mm then 2/3rds of cases it is radicular cyst and not PA granuloma
What can cause numbness
- Trauma
- Infection
- Cyst
- Tumour (benign or malignant)
- TN
What is a residual cyst?
- When radicular cyst persists after loss of tooth (or after tooth successfully RCT)
- Avoid misdiagnosis so be thorough with history - recent XLA
What is a lateral radicular cyst?
- Radicular cyst ass with accesory canal
- located at side of tooth instead of apex
What is a inflammatory collateral cyst? What cysts does it include?
- Inflammatory odontogenic cyst
- Ass with vital tooth
- 2-7% odontogenic cysts
Collective term for
- Paradental cysts
- Buccal bifurcation cyst
What is a paradental cyst?
- Typ occurs at distal aspect of partially erupted mandibular third molar
What is a Buccal bifurcation cyst?
- Typ occurs at buccal aspect of mandibular third molar
Give some examples non-odontogenic examples
- Nasopalatine duct cyst (most common)
- Solitary bone cyst
- Aneurysmal bone cyst
What is a nasopalatine duct cyst? Give the incidence. What is it AKA?
- Developmental non odontogenic cyst
- Arises form nasopalatine duct epithelial remnants
- Occurs in anterior maxilla
Incidence
- most comm 40-60ys
- M> F
AKA incisive canal cyst
What is the presentation of Nasopalatine duct cyst?
- Often asymptomatic
- Pt may note salty discharge
- Larger cysts may displace teeth or cause swelling in palate
- Always involve midline but not always symmetrical
Give the histology of Nasopalatine duct cyst
- variable epithelial lining
- Non keratinsed stratified squamous and modified respiratory
What is the radiographic description of nasopalatine duct cyst?
PA/ Standard max occlusal
- Corticated radiolucency between/ over roots of central incisors
- often unilocular
- May appear heart shaped due to superimposition of anterior nasal spine
CBCT - needed for better visualisation and surgical planning
How can you tell between incisive fossa or cyst?
Incisive fossa
- May or may not be vis on radiographs
- Midline oval shaped radiolucency
- Typ not visibly corticated
Consider transverse diameter
<6mm = incisive fossa
6-10 = consider monitoring
>10 = suspect cyst
What is a Solitary bone cyst? Give AKA
- Non odontogenic cyst without epithelial lining
AKA simple/traumatic/haemorrhagic bone cyst
Give the incidence of solitary bone cyst
- most common 20s
- Male > Female
- Mandible»_space; Maxilla
- Can occur in ass with other bone pathology e.g. fibro-ossesous lesions
What is the clinical and radiographic presentation of Solitary bone cyst?
Clinical
- Asymptomatic and is an incidental finding
- Rarely pain or swelling
Radiology
- Majority in premolar/molar region of mandible (and non tooth bearing areas)
- Variable definition and cortication
- Scalloped margins giving pseudolocular appearance
- Project up between roots of adjacent teeth
What is a Stafne cavity?
- Not a cyst
- Depression in the bone (with cortical bone preserved)
- Only in mandible, exclusively lingual
- Contains salivary or fatty tissue
What is the incidence and presentation of stafne cavity?
- 50 and 60yrs
- Angle or post body of mandible
- Inferior to IAC
- Asymptomatic
- Well defined, corticated radiolucency
- Rarely displaces adjacent structures
What biopsy can be done to obtain material for histology?
Aspiration biopsy (drainage contents)
Incisional biopsy (partial removal)
Excisional biopsy (complete removal)
Give the radiographic features of a radicular cyst
- Well defined
- Round/oval radiolucency
- Corticated margin continuous with lamina dura of non vital tooth
- Larger lesions may displace adjacent structures
- Long standing lesions - external root resorption and or contain dystrophic calcification
Give the histological features of a radicular cyst
- Epithelial lining often incomplete
- Connective tissue capsule
- Inflammation being present in capsule (variable inflammation)
- Cholesterol clefts on the lining
- Mucous metaplasia (epithelial cells become mucous secreting cells)
- Hyaline/rushton bodies
How does this balloon like growth occur in radicular cysts?
- Epithelial rests of Malassez proliferates in PA granuloma
- radicular cyst forms by either proliferating epithelium with central necrosis OR epithelium surrounds a fluid area
- Continued growth of cyst by osmotic effect via semi-permeable wall and cytokine mediated growth
- Bone resorption occurs interleukins activate osteoclastic activity
What is a dentigerous cysts? Give the incidence
-Developmental odontogenic cyst
- Ass with crown of unerupted and usually impacted tooth
- Cystic change to dental follicle
Incidence
- Most common 20-40ys
- male > Female
- Mandible > Maxilla
Give the radiographic features of dentigerous cyst
- Corticated margins attached to cemento-enamel junction of tooth (larger may begin to envelope root of tooth)
- May displace involved tooth
- Tend to be sym initially and when gets larger cysts may expand unilaterally
- Variable displacement of cortical bone (i.e. bony expansion)
Give the histology of dentigerous cyst
- Thin non keratinsed stratified sqaumous epithelium
- Arise from reduce enamel epithelium, fluid acc and expanding cyst formation
- May resemble radicular cyst if inflammed
How do you distinguish between dentigerous cyst and enlarged follicle?
- Normal follicular space 2-3mm
- Measure from surface of crown to edge of follicle
- Consider cyst if follicular space >5mm
- Assume cyst if >10mm
- Also consider cyst if radiolucency is asym
What is an eruption cyst? What teeth is it ass with? What is the txt?
- Variant of dentigerous cyst but conatined within ST instead of bone
- Bluish translucent soft tissue
- ASs with erupting tooth such as incisors - Children usually
TXT
- Small cut to allow to erupt
- No txt as not concerning
What is an Odontogenic Keratocyst (OKC)? Give the incidence
- Developmental odontogenic cyst (no specific relationship to teeth)
Incidence
- Most common 20-30yrs
- Male > Female
- Mandible > Maxilla 3:1
- Posterior > anterior
**BAD NEWS - Very high recurrence rate
Give the radiographic signs of Odontogenic Keratocyst
- Scalloped margins
- 25% multilocular
- Displacement of adjacent teeth (RR uncommon)
- Characteristic expansion as it enlarges in medullary bone space before displacing cortical bone
- Has sig mesio-distal expansion without bucco-lingual expansion
What pre op diagnostic test is useful for OKC? What are the findings?
Cyst aspirate
- Contains squames
- Low sol protein content (<4g per decimeter)
Give the histological features of OKC
- Parakeratotic lining (majority of cysts don’t have keratin)
- Basal palisading (uniform appearance)
- Daughter cysts
- Cell nests (retromolar)
- No rete pegs and thin friable lining (epithelium separates easily so some can be left behind)
What is the presentation of Basal Cell Naeuvus syndrome?
- Multiple odontogenic keratocysts
- Multiple basal cell carcinomas
- Palmar and plantar pitting
- Calcification of intracranial dura mater
- Often at younger age (15yrs)
For an aspiration biopsy what do you use? What fluid can be removed and what can they indicate?
- Wide bore needle with 5-10ml syringe
Can get - Air
- Blood (may indicate Aneurysmal bone cyst)
- Pus (Cystic lesion or infection)
- Cyst fluid (clear straw coloured fluid in inflamm or devlopmentla cysts OR White or cream semi solid indicate keratocyst)
What is the prupose and methodology of Incisional biopsy?
Purpose
- Obtain sample of lining for histopathological analysis
Methodology (under LA)
- Select place where lesion appears superficial
- Raise mucoperiosteal flap
- Remove bone as required
- Incise and rmeove section of lining
Give the surgical options for cystic lesions
- Enucleation
- All cystic lesion removed - Marsupialisation
- Creation of surgical window in wall of cyst , removing contents of cyst & suturing cyst wall to surrounding epithelium
- Encourages cyst to decrease in size, followed by enucleation at later date
Give advantages and disadvantages of enucleation
Advantages
- Whole lining examined pathologically
- Primary closure
- Little aftercare needed
Disadvantages
- Risk of mandib fracture with very larger cysts
- Dentigerous cyst and wish to presever tooth
- old age , ill health
- Clot filled cavity may become infected
- Incomplete removal may lead to recurrence
- Damage to adjacent stuctures
What are the indications of Marsupialisation?
- If enucleation would damage surrounding structures
- Diff access to area
- May allow eruption of teeth by dentigerous cyst
- Elderly or medically compromised unable to withstand extensive surgery
- Very large cysts , risk jaw fracture if enucleation
- Can combine with enucleation at later procedure
Give the advantages and disadvantages of Marsupialisation
Advantages
- Simple to perform
- May spare vital structures
Disadvantages/Contraindications
- Opening may close and cyst may reform
- Complete lining not available for histology
- Diff to keep clean and lots of aftercare needed
- Long time to fill in
- Need obturator to keep wound open
