What is a cyst?
A cyst is a pathological cavity with fluid, semi-fluid or gaseous contents and is not created by an accumulation of pus.
What are the different types of jaw cysts?
1. EPITHELIAL CYSTS:
Odontogenic cysts - inflammatory - developmental
Non odontogenic cysts (nasopalatine duct cyst, nasolabial cyst)
2. NON-EPITHELIALISED PRIMARY BONE CYSTS
- Solitary bone cyst (simple, haemorrhagic)
- Aneurysmal bone cyst
3. INFLAMMATORY ODONTOGENIC CYSTS - Radicular - Paradental
4. DEVELOPMENTAL ODONTOGENIC CYSTS:
Dentigerous (follicular cyst)
Gingival cysts - infants
Gingival cysts– adults
Others- Lateral periodontal cysts, Sialo-odontogenic cysts
What is the relative frequency of odontogenic cysts?
Radicular = 60-70% Dentigerous = 10-15% Keratocyst = 5-10& Nasopalatine = 5-10% Lateral periodontal = <1%
What's a radicular cyst?
Commonest odontogenic cyst (60-70%) Arises from the epithelial cell rests of Malassez in the periodontal ligament, usually after death of the pulp
What are the clinical features of a radicular cyst?
60 - 75% of jaw cysts Peak in 4th and 5th decades Rare in deciduous teeth Common in maxillary incisors due to: - palatal invaginations - small teeth - trauma Symptomless or expansion ‘egg-shell crackling’ Fluctuation Infection leads to pain Non-vital tooth Tooth mobility or displacement
What are the radiographical features of a radicular cyst?
Rounded clearly defined radiolucency Apex of tooth Condensed radiopaque periphery - may be continuous with lamina dura Lateral locations Residual cysts
What is a dentigerous cyst?
Cyst enclosing the crown of an unerupted tooth
Attached to cemento - enamel junction
What are the clinical features of a dentigerous cyst?
10-15% of jaw cysts
Children and young adults
Painless enlargement - missing tooth
Pain and swelling if infected
Tilting of teeth
What are the radiological feautres of a dentigerous cyst?
Crown of unerupted tooth
Well defined, corticated
What's the pathology of a dentigerous cyst?
Clear yellow fluid - cholesterol
Purulent if infected
Lined by flattened, attenuated non-keratinised stratified squamous epithelium
Continuous with reduced enamel epithelium
Mucous and ciliated columnar metaplasia
Fibrous wall + variable inflammation
What's the pathogenesis of a dentigerous cyst?
What's an eruption cyst?
Extra-alveolar follicular cyst
Deciduous tooth or permanent molar
Fluctuant bluish swelling
Haemorrhage into cyst is common
Most spontaneously resolve
What's a gingival cyst?
Bohn’s nodules, Epstein’s pearls
Common in newborn and up to 3 months
Usually rupture or spontaneously involute
2 - 3 mm keratinising stratified squamous epithelium
Arise from Serres rests
Histology of a ginigval cyst:
What's a ginigval cyst in an adult like?
Slow-growing, usually less than 1cm in diameter
Free or attached gingiva or interdental papilla
? odontogenic rests ? implantation
What's an odontogenic keratocyst?
A rare and benign but locally aggressive deveoplmetal cystic neoplasm. Most often affects the posterior mandible.
They're thought to arise from the dental lamina and associated with impacted teeth. Affects males same as females.
Often asymptomatic and only found radiographically but may present with pain, swelling, discharge, pathological fracture, tooth displacement, buccal expansion
High recurrence rate
What are the radiological features of an odontogenic keratocyst?
Well demarcated radiolucent area
Unilocular, often with a scalloped periphery
? dentigerous (envelopmental)
Root or tooth displacement
What's the histopathology of a keratocyst?
Regular stratified squamous epithelium
5 - 8 cells thick
Palisaded basal layer
Corrugated surface, usually parakeratinised
Thin, friable fibrous capsule
Satellite (daughter) cysts
What's the recurrence likelyhood of an odontogenic keratocyst?
6 - 60%
Size and infiltrative nature
Tendency to multiplicity and satellite cysts
Intrinsic growth potential ‘hollow benign neoplasm’
Thin, friable capsule
Genetic - multiple basal cell naevus syndrome (Gorlin and Goltz)
? malignant potential
What's Gorlin-Goltz Syndrome?
Skeletal abnormalities - bifid ribs
- spine defects
Frontal bossing and hypertelorism
Multiple basal cell naevi and carcinomas
Calcification of the falx cerebri
PATCHED (PTCH) gene (9q22)- receptor
What's the pathogenesis of Gorlin-Goltz Syndrome? and how deos enlargement occur?
Pathogenesis = Derived from dental lamina or its remnants - rests or glands of Serres
Varies from cancellous without expansion to large, especially in angle and ramus of mandible
What's an orthokeratinised keratocyst
12% of keratocysts
Basal layer cuboidal or flattened
Granular cell layer
- 4% recurrence rate
What are the clinical features of a lateral periodontal cyst?
Lateral surface of roots
Lower canine/premolar area
Upper lateral incisors
Rare below 20 years
Occasionally swelling +/- pain
Adjacent teeth vital
What are the radiological feautures of a lateral periodontal cyst?
Well defined, uniform radiolucent area lateral to tooth
Usually < 1cm
Round, oval, unilocular
Well defined and corticated
Teeth may be displaced
What's the pathology of a lateral periodontal cyst?
Thin non-keratinised stratified squamous epithelium
Nodular epithelial thickenings or plaques
? derived from cell rests of Malassez
Multilocular variants - botryoid odontogenic cyst
What are the clinical and radiological features of a sialo-odontogenic cyst (glandular odontogenic cyst)?
Rare Middle aged or older Anterior mandible Can be large and destructive Pain and swelling Can recur
Unilocular or multilocular radiolucency Well defined borders
What's the pathology of a sialo-odontogenic cyst?
Epithelium of varying thickness
Irregular or papillary surface with surface cuboidal or ciliated cells
Epithelial whorls or plaques
What's the embryological derivation of odontogenic cysts?
What's a nasopalatine duct cyst?
Incisive canal cyst
Remnants of nasopalatine duct
30 - 60 years
Swelling of midline of palate labial
Pain and discharge - mucoid and salty - purulent and foul
Vitality of anterior teeth