Cysts of the jaws Flashcards
What is a cyst? (2)
A pathological cavity with fluid, semi-fluid or gaseous contents and which is not created by the accumulation of pus
It is usually, but not always, lined by epithelium
Parts of a cyst (3)
Wall (fibrous connective tissue)
Lumen (space where content of cyst sits)
Lining (usually epithelium)
Odontogenic cysts of inflammatory origin (3)
Radicuar cyst
Residual cyst
Collateral/ Paradental cysts
Odontogenic and non-odontogenic developmental cysts (7)
• Follicular cyst -dentigerous cyst -eruption cyst • Odontogenic keratocyst • Lateral periodontal cyst • Gingival cyst • Glandular odontogenic cyst • Calcifying odontogenic cyst • Orthokeratinised odontogenic cyst
Sheffield Oral and Maxfax pathology - cysts % of all cases
13%
Most common jaw lesions (1)
Odontogenic cysts - 55%
Classification of cysts of the jaws (4)
Epithelial cysts
-odontogenic: inflammatory or developmental
-non-odontogenic: nasopalatine duct cyst or nasolabial cyst
Cyst-like lesions
Cysts that are seen quickly in babies (1)
Alveolar cyst
Gingival cyst (1)
Found in adults
Most common jaw cysts (2)
Radicular - 65% Follicular - 20% Keratocyst - 5% Nasopalatine - 5% Others - <5%
Pathogenesis of jaw cysts: need (3)
Source of epithelium
Stimulus for proliferation
Growth and bone resorption
Sources of epithelium (3)
Remnants of Hertwigs root sheath –> radicular cysts
Reduced enamel epithelium –> follicular cysts
Remnants of dental lamina –> keratocysts or gingival cysts
Where does the enamel organ develop from? (1)
The dental lamina
The PDL contains epithelial remnants of Hertwig’s root heath is called (1)
Rest cells of Malassez
Stimuli for proliferation - inflammation (3)
Apical granuloma –> radicular cysts
periodontitis –> inferior lateral periodontal cyst
Pericoronitis –> paradental cysts
Stimuli for proliferation - developmental (3)
Factors largely unknown Dentigerous cyst -eruptive force and proliferation? -hydrostatic pressure? Keratocyst -epithelial proliferation -hydrostatic pressure? -tumour?
Cyst growth and expansion
- Osmosis and hydrostatic pressure
- inflammation, cell shedding and cell death results in increased osmotic pressure
- water drawn in by osmosis, increasing hydrostatic pressure, resulting in unicentric expansion
- e.g. radicular and dentigerous cysts - Proliferation of the lining e.g. odontogenic keratocyst
- Bone resorption
- IL-1 and IL-6
- prostaglandins
- endotoxins
- stimulation and activation of osteoclasts
Radicular cyst (3)
Arise in the periodontal ligament from the
epithelial rests of Malassez as a result of inflammation following death of the pulp.
Always associated with a non-vital tooth.
Apical radicular cysts (1)
at the apex of a tooth associated with
the opening of the root canal
Lateral radicular cysts (1)
at the side of a tooth associated with
a lateral branch of the root canal
Residual radicular cyst (1)
a radicular cyst which has persisted after extraction of the associated tooth
Pathogenesis: radicular cyst (3)
Periapical granuloma (due to caries and non-vital pulp) Proliferating odontogenic epithelium Cyst (with non-k SSE lining)
Features of radicular cyst pathology (5)
Keratin in 2% Cilia in 10% Hyaline bodies in 10% Mucous cells in 15% Cholesterol in 30%
Is this a cyst or a granuloma? Cysts ‘tend’ to be (6)
Larger More radiolucent Well defined Corticated outline Painless BUT only 50% are correctly diagnosed pre-operatively
Size vs pathology (3)
90% of lesions >20mm are cysts
65% of lesions 15-19mm are cysts
65% of lesions 5-9mm are granulomas
Collateral cyst: paradental cyst (2)
A cyst which arises on the lateral aspect of a
tooth as a result of inflammation in a
periodontal pocket. It arises from pocket epithelium.
A particular type of paradental cyst arises at
the buccal aspect of partially erupted molars
Histology: collateral/ paradental cyst (1)
Similar to radicular cyst
What is a follicular cyst? (3)
A cyst which surrounds the crown of an
unerupted tooth and arises from the reduced
enamel (follicular) epithelium.
• dentigerous - associated with an impacted
tooth
• eruption - associated with an erupting tooth
Pathogenesis of a follicular cyst (3)
Impacted tooth
Follicular epithelium proliferates
Cyst forms
Where does an eruption cyst lie? (1)
Just beneath the oral mucosa
Odontogenic keratocyst (3)
• A cyst arising in the tooth bearing area and
characterised by a thin lining of parakeratinised epithelium.
• It arises from the dental lamina or its
remnants
• It may replace a tooth
Pathogenesis of keratocyst (3)
Remnants of dental lamina
Epithelial proliferation
-genetic? trauma?
Cyst develops
Lining of odontogenic keratocyst (2)
Parakeratinsed SSE
-often little on no bucco-lingual expansion
Stats about odontogenic keratocyst (4)
- 62% in males
- 75% in the mandible
- 50% in lower third molar area
- 50% associated with unerupted tooth
Recurrence of keratocysts (3)
• % recurrence varies
between studies
• Fragility of the lining
• Daughter cysts
Odontogenic keratocyst - basal cell naevus syndrome (6)
• AKA ‘Gorlin-Goltz syndrome’
• multiple and recurrent odontogenic keratocysts
• basal cell carcinomas of skin
• frontal bossing
• skeletal abnormalities (e.g. bifid ribs)
• cranial abnormalities (e.g. calcification of falx
cerebri)
Evidence that an odontogenic keratocyst may be a benign neoplasm (4)
High rate of proliferation in the epithelial lining
High rate of recurrence
‘Aggressive’ and infiltrative growth
Association with basal cell carcinoma in BCNS/ Gorlin-Goltz syndrome
• Molecular changes similar to basal cell carcinoma
• PTCH (chromosome 9q) mutation in BCC and Gorlin’s
syndrome
Lateral periodontal cyst (3)
Occurs on the lateral aspect or between the roots of vital teeth.
It is developmental in origin – rests of Serres.
Occasionally it is multilocular and called botryoid odontogenic cyst
Gingival cysts of infants (2)
• arises from dental lamina rests in the alveolar
mucosa of infants
• lined by thin parakeratinised epithelium
Gingival cysts of adults (2)
• arises from dental lamina rests in the attached
gingiva
• lined by thin non-keratinised epithelium
Glandular odontogenic cyst (2)
A cyst characterised by cuboidal or columnar epithelium with mucous production
Forms duct-like or glandular structures
Histology: glandular odontogenic cyst (2)
Epithalial thickenings
Mucous cells and ducts
Nasopalatine duct cyst (2)
Arise in the nasopalatine (incisive) canal from
epithelial residues of the nasopalatine duct
They are lined by respiratory epithelium or stratified squamous epithelium, or often
both
Nasolabial cyst (2)
Arises in the soft tissue overlying the alveolar
process at the base of the nostril, deep to the
nasolabial fold.
It probably arises from remnants of the nasolacrimal duct and is usually lined by
pseudostratified columnar epithelium
Cyst-like lesions (3)
Cystic lesions in the jaws, without an epithelial lining:
- Solitary (simple) bone cyst
- Stafne’s bone cavity
