Oral histopathology with cysts Flashcards

1
Q

What is a cyst?

A

Pathological cavity having fluid, semi-fluid or gaseous contents and which is not created by accumulation of pus (pus can occur once cyst becomes infected).
Can be wholly or partly lined by epithelium

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2
Q

Give some examples of inflammatory cysts?

A

Radicular
Residual
Inflammatory collateral cysts - paradental, mandibular buccal bifurcation

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3
Q

Examples of developmental cysts

A

Dentigerous cyst
Odontogenic keratocyst
Gingival cysts

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4
Q

Explain aetiology of radicular cyst

A

ALWAYS associated with NECROTIC pulp - intiated by chronic inflammation apical PDL
Proliferation of RESTS OF MALLASEZ from Hertwig’s epithelial root sheath

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5
Q

What is a residual cyst?

A

Remnants of radicular cyst that remain after exctraction of affected tooth
Can get lateral residual cysts associated with accessory canal

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6
Q

Where is a radicular cyst most common?

A

Maxillary lateral incisors

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7
Q

How might a radicular cyst present clinically?

A

Often asymptomatic so incidental finding
Typically slow-growing and limited expansion
Might get “egg shell” crackling upon palpation of the swelling
Mobility of teeth
Discolouration of gingivae/ teeth

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8
Q

How does a radicular cyst present histologically

A

Incomplete epithelial lining
Connective tissue capsule - can have inflammation in this
Rests of malassez
Cholesterol clefts
Mucous metaplasia
Hyaline/ rushton bodies

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9
Q

How do radicular cysts form?

A

Periapical periodontitis to periapical granuloma - when it gets >15mm = radicular cyst

Proliferating epihtelium with central necrosis
OR
Epithelium surrounds fluid area

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10
Q

Where do paradental cysts typically occur and what type of cyst is it?

A

Typically distal aspect of partiall-erupted mandibular third molar
Inflammatory collateral cyst

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11
Q

Where do buccal bifurcation cysts occur and what type of cyst is it?

A

Typically occur at buccal aspect of mandibular first molar
Odontogenic inflammatory collateral cyst

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12
Q

What type of cyst is a dentigerous cyst and what is the aetiology?

A

Developmental odontogenic cyst
Associated with crown of unerupted (usually impacted) tooth - M3M and maxillary canines
Cystic changes of the dental follicle

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13
Q

Radiological signs of dentigerous cysts?

A

Corticated margins attached to CEJ of tooth
May displace involved tooth
Well-defined unilocular
Attached to crown of unerupted tooth
Typically symmetrical - larger cysts may begin to expand unilaterally

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14
Q

Histology of dentigerous cyst?

A

Thin, non-keratinised stratified squamous epithelium
Flat basement membrane
May resemble radicular cyst of inflamed

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15
Q

Non-cystic radiolucent lesions differential diagnosis

A

Odontogenic tumours - ameloblastoma, ameloblastic fibroma
Giant cell lesions - peripheral/ central giant cell granuloma
Fibro-cemento osseous lesions
Radiolucnet non-odontogenic tumours - squamous cell carcinoma, haemangioma

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16
Q

What type of cyst is odontogenic keratocyst and the aetiology/ features?

A

Developmental odontogenic cyst
Arises from REST OF SERRES - remnants of the dental lamina
Unusual growth pattern with high risk of recurrence

17
Q

What is the growth pattern for odontogenic keratocyst?

A

Unusual - anterior-posterior direction
Can reach large size without causing gross bony expansion

18
Q

What is an odontogenic keratocyst (OKC) and incidence?

A

Developmental odontogenic cyst - no specific relationship to teeth
Most common 2nd and 3rd decade
M>f
Mandible over maxilla
Posterior>anteiror

19
Q

Histology OKC

A

Thin friable lining
Parakeratosis
Daughter cysts
Loss of keratin if inflamed

20
Q

General management of cysts?

A

Referral
Initial consultation
Special investigation - plain film radiograph/ CBCT
Biopsy
Diagnosis
Treatment plan and discussion
Treatment options
- Enucleation
- Marsupialisation
- Surgical resection

21
Q

What is cyst enucleation?

A

Removal of entire cyst lining and contents
Depends on size of cyst and type

22
Q

What is cyst enucleation most useful for treating?

A

Radicular
Residual
Dentigerous
Keratocysts

NOT FOR AMELOBLASTOMA

23
Q

Complications of cyst enucleation?

A

Mainly related to size, position and type of cyst
Damage to IAN
Communication with maxillary sinus OAC
Pathological fracture of mandible
Risk of recurrence

24
Q

What is purpose of marsupialisation?

A

Creating a window in the cyst to allow for decompression of pressure and subsequent reduction in size for enucleation

25
Q

Complications of marsupialisation?

A

Needs further surgery for removal cyst
Long treatment before completion
Chance of re-infection
Uncomfortable
May close over if no grommit

26
Q

What is segmental resection of a cyst and what are they mainly used for?

A

Removal of cyst with margin of normal bone
Mainly used for ameloblastoma and sarcoma

27
Q

Treatment for radicular cyst?

A

RCT the affected cyst if small
Can then consider peri-radicular surgery to remove cyst
OR
Extract necrotic tooth and see if cyst shrinks
If cyst becomes larger/ does not go away, enucleate

28
Q

Give an example of an epithelial, non-odontogenic cyst?

A

Nasopalatine cyst

Note - originates from epithelial remnants of naso-palatine duct

29
Q

What are the radiological features of a naso-palatine cyst?

A

Well-defined round, ovoid or HEART-shaped radiolucency
Sclerotic margin

30
Q

Histopathology of a nasopalatine cyst

A

Lined by stratified squamous & respiratory or cuboidal epithelium
Neurovascular bundles found in capsule

31
Q

Clinical features of a nasopalatine cyst?

A

M>F
5th and 6th decade
May be asymptomatic
Slowly enlarging swelling anterior region midline of palate

32
Q

Radiological signs OKC

A

Scalloped margins
Oval
Uni/ multi-locular - most are multi-locular
Well-defined uniform radiolucency