Odontogenic cysts Flashcards by Francesca Norton

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.

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What are the different types of jaw cysts?

EPITHELIAL CYSTS:

 Odontogenic cysts - inflammatory - developmental

 Non odontogenic cysts (nasopalatine duct cyst, nasolabial cyst)

NON-EPITHELIALISED PRIMARY BONE CYSTS
- Solitary bone cyst (simple, haemorrhagic)
- Aneurysmal bone cyst
INFLAMMATORY ODONTOGENIC CYSTS - Radicular - Paradental
DEVELOPMENTAL ODONTOGENIC CYSTS:

 Dentigerous (follicular cyst)

 Eruption cyst

 Gingival cysts - infants

 Gingival cysts– adults

 Keratocyst

 Others- Lateral periodontal cysts, Sialo-odontogenic cysts

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What is the relative frequency of odontogenic cysts?

Radicular = 60-70% Dentigerous = 10-15% Keratocyst = 5-10& Nasopalatine = 5-10% Lateral periodontal = <1%

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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

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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

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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

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What is a dentigerous cyst?

Cyst enclosing the crown of an unerupted tooth

Attached to cemento - enamel junction

Follicular cyst

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What are the clinical features of a dentigerous cyst?

10-15% of jaw cysts

Children and young adults

Permanent teeth

M:F 1.6:1

Painless enlargement - missing tooth

Pain and swelling if infected

Tilting of teeth

Root resorption

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What are the radiological feautres of a dentigerous cyst?

Crown of unerupted tooth

Permanent teeth

Round, unilocular

Well defined, corticated

Uniformly radiolucent

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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

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What’s the pathogenesis of a dentigerous cyst?

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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

 Marsupialise

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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

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Histology of a ginigval cyst:

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What’s a ginigval cyst in an adult like?

 Slow-growing, usually less than 1cm in diameter

 Free or attached gingiva or interdental papilla

 Tooth vital

 Pathogenesis:

? odontogenic rests ? implantation

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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.

CLINICAL:

Often asymptomatic and only found radiographically but may present with pain, swelling, discharge, pathological fracture, tooth displacement, buccal expansion

10% multiple

High recurrence rate

What are the radiological features of an odontogenic keratocyst?

Well demarcated radiolucent area

Unilocular, often with a scalloped periphery

 Multilocular

? 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 keratocysts

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

Enlargement =

 Varies from cancellous without expansion to large, especially in angle and ramus of mandible

 Mural growth

What’s an orthokeratinised keratocyst

 12% of keratocysts

 Basal layer cuboidal or flattened

 Orthokeratinised surface

 Granular cell layer

 Behaviour

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

Usually asymptomatic

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)?

CLINICAL FEATURES:  Rare  Middle aged or older  Anterior mandible  Can be large and destructive  Pain and swelling  Can recur RADIOGRAPHY:  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 Mucous cells Epithelial whorls or plaques

What's the embryological derivation of odontogenic cysts?

See image

What's a nasopalatine duct cyst?

 Incisive canal cyst  Remnants of nasopalatine duct  M:F 4:1  30 - 60 years  Swelling of midline of palate labial  Pain and discharge - mucoid and salty - purulent and foul  Vitality of anterior teeth

What's the radiology of a nasopalatine duct cyst?

 Well defined radiolucency between roots of central incisors  Roots may diverge  Intact lamina dura

What's the histopathology of a nasopalatine duct cyst?

 Respiratory type epithelium  Stratified squamous epithelium  Blood vessels and nerves in wall

What are the clinical feautres of a nasolabial duct cyst?

Swelling in nasolabial fold below alae and leading to loss of fold Sometimes bilateral Swelling, pain, difficulty in nasal breathing or wearing denture

What's the pathogenesis and histopahtology of a nasolabial cyst?

PATHOGENESIS:  ? epithelium enclosed at a site of ‘fusion’ of globular, lateral nasal and maxillary processes - unlikely  ? remnants of embryonic nasolacrimal duct HISTOPATHOLOGY:  Non-ciliated columnar, respiratory type or stratified squamous epithelium

What's an aneurysmal bone cyst?

A type of non-epithelialised primary bone cyst: most common in Radiolucent area bulging into adjacent soft tissue Blood filled spaces Giant cells, haemorrhage, osteoid ? associated fibro-osseous lesion

What's a simple bone cyst?

A type of non-epithelialised primary bone cyst: ## Footnote  Solitary, haemorrhagic, traumatic  Rare  Mandible, usually in second decade  Radiolucent area extending between roots, usually without expansion  Resolves with minimal intervention