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Cysts of the Face & Jaws I-III

Common Cysts of the Jaws and Head & Neck
- Most important part of bone lesions topic
...
Cysts are frequently, but not always, lined by epithelium
...

• Lumen & Contents
...

• Epithelial Lining
...

• Inflammation
...

• A Mechanism to allow it to Enlarge
...




Classification Terms for Jaw Cysts
• Odontogenic Cysts: Lined by an epithelium derived from Odontogenic Epithelium (arising in tissues
that give rise to teeth)
...

• Inflammatory: Inflammation is the stimulus causing proliferation of the epithelium and cyst
formation
...


CLASSIFICATION OF COMMON JAW CYSTS
• DEVELOPMENTAL
o Odontogenic:
! Dentigerous/Eruption Cysts
...

! Lateral Periodontal Cyst
...

o Non-Odontogenic:
! Nasopalatine Cyst
...

! Thyroglossal and Branchial Cyst
...

o Radicular (apical/lateral) & Residual
...

o Solitary Bone Cyst
...

• Salivary Cysts
...

• Globulomaxillary Cyst
...
e
...

o Primordial Cyst
...


Relative Incidence of Cyst
• Radicular Cysts " 68%
...

• Odontogenic Keratocysts " 3%
...

Others are rare
...


•


RADICULAR CYSTS (Inflammatory Dental Cysts)
Most Common (68%)

RADICULAR CYSTS: Starts as an apical granuloma in which
epithelium proliferates in response to inflammation
...
(e
...
due to
caries/trauma)
• Apical, lateral or residual
...

• Present in middle age (but with wide range)
...

• Very rare on deciduous teeth
...
Caries as labeled
on tooth
...

Inflammation may go through stages of growth and
non-growth
...
Slow/fast growing?
• SHAPE: Unilocular/Multi-locular/Pseudolocular (suggestion of multi-locularcy but it is not obvious)
• OUTLINE: Well defined? – Can you draw around the edge?
...

• RELATIVE RADIOLUCENCY: Uniform/Non-uniform?
• AFFECT ON OTHER STRUCTURES:
o Radiographically
o Clinically
o E
...
expansion of jaw? How does it affect teeth – displacement/resorption etc
...


Examples
• SITE: Radiolucency at apex of a non-vital tooth
...

• SHAPE: Unilocular
...
Corticated
...

• AFFECT ON OTHER STRUCTURES: Radiographically none, but
clinically an expansion/enlargement in the buccal sulcus
...
(You don’t have to
reach a Differential Diagnosis – this is a helpful example of how

it would present)
...

• Important to know how to describe

lesions
...

radiographs
...

• Interpreting radiographs – 1st
• SHAPE: Unilocular
...

• OUTLINE: Well defined
...

Should be able to identify
• RELATIVE RADIOLUCENCY: Uniform radiolucency
...

• AFFECT ON OTHER STRUCTURES:
• Learn the typical features of cysts
...

o Clinically – an expansion/enlargement in the buccal sulcus
...


RESIDUAL CYST (cyst left behind)
• A radicular cyst from which the non-vital tooth has been removed
...


Histology of Residual Cysts
Similar/Identical to Radicular Cysts except that:
• Inflammation subsides as the cause has been removed
...

• Mural nodules appear
...
Residual cysts may be less inflamed and the epithelium may be
less hyperplastic
...
Need to ensure you remove it
to prevent a Residual cyst
...

• Some called “Mandibular
Infected Buccal Cysts”

• Occur in vital teeth, recently
erupting
...

• Thick Fibrous Wall/Capsule – usually packed with inflammatory cells
...

• Cholesterol cysts
...


Why do Inflammatory Cells Enlarge?
• Radicular Cysts have an internal hydrostatic pressure of 60-100cm water
...

• Much high molecular weight protein is secreted into cysts, (e
...
immunoglobulin)
...

• Internal pressure probably fluctuates with inflammation
...

• Inflammatory mediators from the wall can induce resorption
...


How fast do they grow?

• Slowly
...

• In children, to 5cm diameter in 2 years
...

• Structures around may be displaced – radiological evidence
...

• But shape is constrained by resistant tissues: cortical bone, teeth and mucoperiosteum
...

• Odontogenic
...


Commonest on Lower 8, upper 3, upper 8
...

Reduced enamel epithelium separates from enamel to form the
cyst cavity
...

- Especially lower 8’s
...

- Any teeth that struggle to erupt into the oral cavity
...
Fluid

collects between the crown of the tooth and the

REE ! continues to expand to form a cyst
...


These types of cysts should be sent in for
examination
...

SIZE: Several cm in diameter
...

OUTLINE: Well defined & Corticated
RELATIVE RADIOLUCENCY: Uniformly Radiolucent
...


Dentigerous Cyst Histology
• In early stages looks like Reduced Enamel Epithelium (REE) – 2 cells thick
...

• If inflamed, looks like a Radicular cyst
...

• They have an internal hydrostatic pressure
...

• Growth pattern is as for radicular cysts and this aids diagnosis
...

• SIZE: Several cm in diameter
...


•
•
•

OUTLINE: Well defined
...

RELATIVE RADIOLUCENCY: Uniformly radiolucenct
...

o Clinically – an expansion is visible in the buccal sulcus
...


•


ODONTOGENIC KERATOCYST (OKC)
Third most common – 3%
...


• Commonest at angle of mandible, behind or instead of 8s
...

• Unilocular/Multilocular
...

• Arise from dental lamina rests
...

• They can recur
...

• No other cyst grows in this way (though solitary bone cysts
are similar)
...

Grow at a slow pace
...


Cant diagnose an Odontogenic Keratocyst
from a Radiograph alone – but include in
your differential diagnoses
...

• SIZE: Can get quite large –
especially antero-posteriorly
...

• OUTLINE: Well defined,
Corticated
...



If the tooth involved in the cyst is vital then it is NOT
a Radicular cyst
...

- pseudo-locularcy – suggestion of
multilocularcy but it is not obvious
...










Histopathology
• Regular Stratified Squamous Epithelium
...

• Palisaded basal layer
...

• Thin, friable fibrous capsule – little inflammation
...

• Flanel of Keratin – don’t see this with other cysts





How do Odontogenic Keratocysts Grow?
• They have no internal pressure
...

• The lining has a high mitotic activity and the wall secretes bone resorbing factors
...

• Teeth are not displaced, cortical bone is not resorbed
...

• Ability to penetrate and burrow – more like a ‘tumour’
...

• Thin wall and piecemeal removed
...

• Growth potential
...

• Or is a neoplasm?

Basal Cell Naevus Syndrome (BCNS)
• BCNS, Gorlin’s or jaw cyst bifid rib syndrome
...

• Multiple basal cell carcinomas start to appear in
adolescence but often seen in 3rd decade
...

• Frontal Bossing (large, prominent forehead), mild skeletal
class 3, skin pitting + more
...

• Cause is mutation of patched gene active in developmental
patterning
...

• Inheriting one mutant allele causes many skeletal features
...


Hedgehog Pathway
• Responsible for developmental positioning
...

• Named after larval appearance of Cuticular Denticles
...

• Smoothened accumulates
...

• Genes including growth factors transcribed
...


Histology of Cysts in BCNS Syndrome

Is exactly the same as in non-syndrome Odontogenic Keratocysts
...


Are OKC Benign Neoplasms?

• YES:
# Recur
...

# Soft tissue spread
...

# Association with Patched gene mutation
...

Can remove effectively but not conservatively
...

Resolve on marsupialization
...




INCISIVE CANAL CYST or NASOPALATINE DUCT CYST

• Developmental
• Non-Odontogenic

INCISIVE CANAL CYST
• Commonest non-odontogenic cyst
...

• Age ranges 30-60 but wide
...

• Teeth are vital
...

• The foramen/opening is palatal and therefore the swelling is usually in the palate
...

- SITE: Anterior midline of maxilla (same place always)
- SIZE: Usually a couple of mm in diameter (depends on time of discovery)
- SHAPE: Unilocular
...

- OUTLINE: Well defined
...

- RELATIVE RADIOLUCENCY: Uniformly radiolucenct
...

- Differential Dx: Incisive Canal/Nasopalatine Duct Cyst
...

• Blood vessels and nerves in wall
...


Nasolabial Cyst
• In nasiolabial fold, upper buccal sulcus and lip
...


• May be partial nasal obstruction
...

• Probably developmental disturbance of nasolacrimal duct
...











Lateral Periodontal Cyst
• Developmental Odontogenic Cyst
...

• Mid age
...

• Thin epithelial lining with plaque like thickenings
...

• High risk of recurrence
...

• More pronounced growth potential
...

• Adults – Possibly a relative of Lateral Periodontal Cyst
...

o No great significance
...

o Often mangled on removal
...

• Wide age range
...

• Multilocular or unilocular
...

• Not be confused with central mucoepidermoid carcinoma of jaws
...

• About 1/3 rd are infected
...

• Asymmetry
...

• Fluid discharge, spontaneous, on extraction or RCT
...


Examination:
• Bluish colour when beyond bone
...

• Fluctuation
...

• Radiographs
...

• Aspiration
...


Role of Biopsy in Cyst Diagnosis
• Odontogenic Keratocyst and some rarer entities have diagnostic appearances – unless inflamed
...

• Excludes solid tumours and cyst-like lesions
...

• Microscopy may show keratin or signs of inflammation
...

• Soluble protein level:
o <3g/100ml in odontogenic keratocysts,
o >4g/100ml in inflammatory cysts/others
...



How do you tell a Cyst from the Antrum?
• They are both epithelial-lined cavities
...

• Both may have a narrow cortical bone layer
...

• Vitality of teeth
...

• Wall of cyst is not concave
...


How do you Treat Cysts?
• Enucleation (The process of completely removing an
organ, tumour, or cystic lesion)

• Marsupialisation (An operative technique for the
removal of a cyst in which an incision is made into the cyst and the cyst lining is sutured to the oral
mucosa, thus creating a pouch which is open to the oral environment
...

• Combination
...

• Carnoy’s solution and enucleation
...

• Is sometimes preceeded by dysplasia
...

• A rare occurrence and often diagnosed after malignancy supervenes
...


• It is a cavity usually with an epithelial lining but it can become infected and will then contain pus
...


• The important thing to remember about a cyst abscess is that it needs to be treated by antibiotics and
usually drainage (as the total volume of pass in a cyst can be very large and cause significant systemic
symptoms) and then the cyst will still need to be treated
...


• Thus if a cyst becomes infected the question is not whether it then becomes an abscess or is a cyst, it is both
– an abscess in a cyst
...


•
All three are inflamed, but the development of pus defines an abscess
...

If an abscess forms it will usually drain through a sinus after a short period
...

Whether there is acute or chronic inflammation in a periapical granuloma or a cyst will vary over time
...

Conversely, abscesses are always acutely inflamed

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