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Oral-Maxillofacial Surgery > Cysts > Flashcards

Cysts Flashcards

1
Q

What is a cyst?

A

A pathological cavity having fluid, semi-fluid or gaseous contents and which is not created by the accumulation of pus.

Wholly or partly lined by epithelium.

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2
Q

What radiographs might you request?

A

Initially PA radiograph, occlusal or OPT.
- choice dictated by patient history and clinical examination.

Supplemental
- CBCT
- Facial radiographs- posterior-anterior mandible or occipitomental views.

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3
Q

What are the limitations of initial radiographs in the dental setting?

A

They are a 2D image of a 3D structure- don’t know why extent of the lesion bunco-lingually.

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4
Q

What are the radiographic features of a cyst?

A

Location

Shape- often spherical or egg-shaped. most grow by hydrostatic pressure.

Margins- often well defined and corticated.

Locularity-often unilocular but can be multilocular or pseduolocular.

Mulitplicity- usually single but can sometimes be bilateral or multiple.

Effect on surrounding anatomy- displacement of cortical plates, adjacent teeth, maxillary sinus, inferior alveolar canal.
Root resorption may occur with chronic cysts.

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5
Q

If a cyst becomes infected, how might that manifest itself radiographically?

A

Cysts may lose definition and cortication of margins if they become infected.

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6
Q

What can epithelial cysts be classified as?

A

Odontogenic- inflammatory or developmental

Non-odontogenic.

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7
Q

What are odontogenic cysts?

A

Occur in tooth-bearing area.

Most common cause of bony swelling in the jaws- 90% of all cysts in the oral and maxillofacial region.

Lined with epithelium.

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8
Q

What are the odontogenic sources of epithelium?

A

Rests of Malassez- remnants of Hertwig’s epithelial root sheath

Rests of Serres- remnants of the dental lamina

Reduced enamel epithelium- remnants of the enamel organ.

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9
Q

What are the most common odontogenic cysts?

A

Radicular cyst or residual cyst if the tooth has been extracted.
- 60% of odontogenic cysts.

Dentigerous cyst and eruption cyst
- 18% of odontogenic cysts.

Odontogenic keratocyst
- 12% of cysts in the maxillofacial region.

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10
Q

What is a radicular cyst?

A

Most common jaw cyst.

Inflammatory odontogenic cyst, which is around the apex of a non-vital tooth.

Initiated by chronic inflammation at apex of tooth due to pup necrosis- proliferation of epithelium- rests of Malassez.

Tooth is often asymptomatic.

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11
Q

What is the aetiology of a radicular cyst?

A

Most common in 4th and 5th decades.
60% in the maxilla and 40% in the mandible.
Can involve any tooth- frequently the lateral incisor region.

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12
Q

What is the radiographic presentation of a radicular cyst?

A

Round or ovoid radiolucency at the root apex of a non-vital tooth.

Unilocular, well defined.

Uniform radiolucency.

Corticated margin continuous with lamina dura of non-vital tooth.

Larger lesions may displace adjacent structures.

Long standing lesions may cause external root resorption and/or dystrophic calcification.

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13
Q

How does a radicular cyst present clinically?

A

Often asymptomatic but may cause pain if it becomes infected.

Typically slow growing with limited expansion.

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14
Q

What is the difference between a radicular cyst and a periapical granuloma?

A

Difficult to differentiate radiographically- radicular cysts tend to be larger
- if radiolucency diameter is greater than 15mm, it is likely to be a radicular cyst.

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15
Q

Describe the histological features of a radicular cyst.

A

Regular lining of non-keratinised squamous epithelium.
Deposits of cholesterol
Vascular capsule
Inflammatory infiltrate

Ruston bodies may be present in odontogenic cysts.

Mucous metaplasia

Cholesterol clefts

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16
Q

How does a granuloma develop into a radicular cyst?

A

Epithelial rests of Malassez proliferate in periapical granuloma.
- ballooning type growth, all aspects of the cyst will increase in size at the same rate and same time.

Radicular cysts may form by- proliferating epithelium with central necrosis or epithelium surrounds fluid area.

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17
Q

What is the mechanism by which a radicular cyst continues to grow once it has been formed?

A

Osmotic effect with semi-permeable wall

Cytokine mediated growth.

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18
Q

What special investigations would you request for a potential cyst?

A

Sensibility tests
CBCT

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19
Q

Why might someone with a cyst C/O a cracking noise?

A

As you press on the swelling, the bone is thinner in this area due to the cyst, so the pressure that is placed on the bone cause. cracking sound.

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20
Q

What symptoms might someone present with that has a cyst?

A

Mobility of teeth
Swelling
sensitivity of teeth
Numbness- cyst may be pressing on the nerve.
Discolouration of teeth
Tenderness

Some may not have any symptoms at all.

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21
Q

if a cyst was impinging on the maxillary sinus, what symptoms may the patient present with?

A

Blocked nose
Sinusitis- headaches, worse when leaning forwards.
Numbness in the infraorbital region.

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22
Q

What is a residual cyst?

A

When a radicular cyst persists after loss of the tooth.

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23
Q

What is a lateral radicular cyst?

A

Radicular cyst associated with an accessory canal.

Located on the side of the tooth instead of the apex.

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24
Q

What type of fluid might you see in a radicular cyst?

A

Might be watery, straw-coloured fluid to a semi solid brownish material.

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25
Q

What would be the standard treatment for a radicular cyst?

A

Extraction of associated tooth and simple enucleation.

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26
Q

What is an inflammatory collateral cyst?

A

Type of inflammatory odontogenic cyst, associated with a vital tooth.

Occur on lateral (usually ducal) aspect of a partially erupted, vital tooth.

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27
Q

What are the two type of inflammatory collateral cyst?

A

Paradental cyst and mandibular buccal bifurcation cyst.

28
Q

What is a paradental cyst?

A

Makes up 60% of inflammatory collateral cysts.

Most frequently associated with a partially erupted mandibular third molar- inflammatory stimulus is pericoronitis.

Usually on the distal aspect.

29
Q

What are the radiographic features of a paradental cyst?

A

Well defined radiolucency related to the neck of a tooth and coronal third of root.

30
Q

What is a mandibular buccal bifurcation cyst?

A

Form of inflammatory collateral cyst that usually originated at the buccal aspect of erupting first molar.

31
Q

What is a dentigerous cyst?

A

Developmental odontogenic cyst.

Associated with crown of unerupted (and usually impacted) tooth.

Cystic change of the dental follicle.

32
Q

What is the aetiology of a dentigerous cyst?

A

Most common in 2nd-4th decades. and in males compared to females.

More common in the mandible compared to the maxilla.

Commonly associated with impacted mandibular third molars.

33
Q

What are the radiographic findings of a dentigerous cyst?

A

Corticated margins attached to cemento-enamel junction of tooth.
- encompasses the whole crown of the tooth.

Larger cysts may begin to envelope root of tooth.

May displace involved tooth.

Tend to be symmetrical initially but larger cysts may begin to expand unilaterally.

Variable displacement of cortical bone.

34
Q

What is the histological findings of a dentigerous cyst?

A

Thin non-keratinised stratified squamous epithelium.

May resemble radicular cyst if inflamed.

Epithelium originates from the reduced enamel epithelioum- remnants of the enamel organ.

35
Q

How can you tell the difference between a dentigerous cyst and an enlarged follicle?

A

Consider cyst if follicular space 5mm or more- measure from the surface of the crown to edge of follicle.

Normal follicular space is 2-3mm.

Consider cyst if radiolucency is asymmetrical.

36
Q

How would you treat a dentigerous cyst?

A

Enucleation if small or marsupialisation if it is larger.

Extract the tooth

37
Q

What is an eruption cyst?

A

Variant of dentigerous cyst but contained within soft tissue rather than bone.

Overlies an erupting tooth- most frequently deciduous incisors or first permanent molars.

38
Q

What is an odontogenic keratocyst?

A

Developmental odontogenic cyst.

39
Q

How does an odontogenic keratocyst develop?

A

Arises from the cells of serres- remnants of the dental lamina.

Unusual growth pattern with a high recurrence rate- enlarges in the anterior-posterior direction.

Can reach larges sizes without causing bony expansion.

40
Q

Where are the odontogenic keratocyts most commonly found?

A

Posterior mandible
More common in males than females
Most common in 2nd and 3rd decades

41
Q

What is the radiographic presentation of an odontogenic keratocyst?

A

Oval shaped radiolucency, well-defined, uniform radiolucency
Scalloped margins
Uni- or multilocular
Often causes displacement of adjacent teeth
Significant mesio-distal expansion before it causes bunco-lingual expansion.

42
Q

If you suspect an odontogenic keratocyst based off a radiograph, what would you do?

A

Aspirational biopsy from the cyst

Contains squames
Low soluble protein content- less than 4g/dL.
Thick white/creamy, semi-solid material within the cyst.

43
Q

Describe the histology of an odontogenic keratocyst.

A

Parakeratinised stratified squamous lining.
- Corrugated epithelial lining.

Thin friable lining- makes it difficult for surgery- high recurrence rate.
- grows by infiltration.

Palisading of basal cells.

No rete pegs.

Satellite cells- can cause recurrence.
- Epithelium separates from the wall, resulting in islands of epithelium within the tissue.

Cell rests.

44
Q

What is basal cell nevus syndrome?

A

Present with multiple odontogenic keratocysts.

Multiple basal cell carcinomas of the skin.

Skeletal abnormalities- Calcification of intracranial dura mater.

Characteristic facial features
- Frontal and temperalparietal bossing.
- Mild mandibular prognathism.
- Mild telorism.

Abnormalities of calcium and phosphate metabolism.

45
Q

What is a lateral periodontal cyst?

A

Associated with lateral root surface of tooth root of a vital tooth.

Usually asymptomatic and an incidental finding.

Most commonly found in the canine and premolar region in the mandible and then the anterior maxilla.

46
Q

What is the treatment for a lateral periodontal cyst?

A

Simple enucleation.

47
Q

Give examples of non-odontogenic cysts.

A

Nasopalatine duct cyst

Solitary bone cyst- non-epithelial jaw cyst

Aneurysmal bone cyst- non-epithelial jaw cyst.

48
Q

What is a nasopalatine duct cyst?

A

Developmental non-odontogenic cyst.

49
Q

What does a naso-palatine duct cyst arise from?

A

Nasopalatine duct epithelial remnants.
Occurs in the anterior maxilla.

50
Q

What is the clinical presentation of a nasopalatine duct cyst?

A

Most common in 4th-6th decades.
More common in males than females
Often asymptomatic
Patients may get a salty discharge
Larger cysts may displace teeth or cause swelling in the palate.

51
Q

What is the radiographic presentation of a nasopalatine duct cyst?

A

Unilocular, heart shaped radiolucent lesion.
Corticated radiolucency between/over roots of central incisors.

52
Q

Describe the histology of nasopalatine duct cyst.

A

Lined by non-keratinised stratified squamous and cuboidal epithelium.

53
Q

How can you tell the difference between a nasopalatine duct cyst and a normal incisive fossa?

A

If the radiolucency is greater than 10mm- assume cyst.

54
Q

Give examples of non-epithelial jaw cysts.

A

Solitary bone cyst

Aneurysmal bone cyst

Stafne’s idiopathic bone cavity

55
Q

What are the distinguishing features of a solitary bone cyst?

A

Most common in the mandible- usually in premolar and molar region.
Usually asymptomatic but may cause bony expansion.

Radiographically-
- Has a distinct scalloped margin with an irregular outline.
- Some are corticated, some aren’t.
- May project between the roots of molars.

56
Q

What is Stafne’s idiopathic bone cavity?

A

Not a cyst but commonly mistaken as one.

Occurs in the mandible- often inferior to the IAN.
Well-defined, often corticated radiolucent.
Asymptomatic- chance finding on a radiograph.
rarely displaces adjacent structures.

Contains salivary and fatty tissue.

57
Q

What colour fluid would indicate a specific cyst?

A

Clear straw coloured fluid- inflammatory or developmental cyst.

White or cream semi-solid- keratocyst.

58
Q

Describe the process of diagnosis and treatment of a cyst.

A

Initial consultation.
Special investigations- CBCT.
Biopsy- aspirational or incisional (would do incisional if thinking it is a keratocyst)
Diagnosis
Treatment planning
Treatment options- enucleation, marsupialisation, surgical resection.

59
Q

What is enucleation?

A

Removal of the entire cystic lesion- treatment of choice most of the time.

60
Q

What are the advantages and disadvantages of enucleation?

A

Advantages-
- Whole lining can be examined pathologically.
- Primary closure
- Little aftercare needed

Disadvantages-
- Risk of mandibular fracture if a very large cyst
- Damage to adjacent structures- IAN
Communication with maxillary sinus.
- Clot-filled cavity may become infected
- Incomplete removal of the lining may lead to recurrence.

61
Q

What is marsupialisation?

A

Creation of a surgical window in the wall of the cyst, removing the contents of the cyst and suturing the cyst wall to the surrounding epithelium.

Encourages the cost to decrease in size.

62
Q

What are the indications for marsupialisation?

A

Large cyst- risk of fracture to mandible
Risk of damage to adjacent structure
Difficult access to the area.
Elderly or medically compromised patients who wouldn’t cope with a long surgical procedure.
May allow eruption of tooth affected by a dentigerous cyst.

63
Q

What might you use to keep a marsupialisation window open?

A

Obturator

64
Q

What would be the contraindications for marsupialisation?

A

Risk that the opening will close up and cyst may reform
Difficult to keep clean and lots of aftercare needed
Takes a long time to close up
Complete lining not available for histology

65
Q

What is the purpose of an incisional biopsy?

A

To obtain a sample of the lining for histopathological analysis.

66
Q

Describe the methodology of an incisional biopsy?

A

Anaesthetise the area using LA.

Select place where lesion appears superficial.

Raise a mucoperiosteal flap.

Remove bone as required- using rangers or a round bur.

Incise and remove a section of lining.

Procedure can be combined with marsupialisation.

Oral-Maxillofacial Surgery (6 decks)

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