Cysts

Question 1

How can you categorise cysts?

Answer 1

Asymptomatic/symptomatic
Slow growing/fast growing
Indolent/destructive

Question 2

In general are cysts benign?

Answer 2

Yes

Question 3

What is a cyst?

Answer 3

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

Question 4

How can cysts present?

Answer 4

Often asymptomatic
Found as incidental finding
Blue/red swelling
Pain and profusion if infected
Tooth mobility

Question 5

What radiographs should be taken when investigating a cyst?

Answer 5

First line:
- PA
- Occlusal
- Panoramic

Can consider:
- CBCT
- Facial
- PA mandible
- Occipitomental view

Question 6

What features of a cyst should be noted on a radiograph?

Answer 6

Location
Shape (egg shaped)
Margins (well defined, corticated)
Locularity (Uniocular, multi-ocular)
Multiplicity
Effect on surrounding anatomy
Inclusion of unerupted teeth

Question 7

By what mechanism do cysts grow?

Answer 7

Hydrostatic pressure

Question 8

What types of developmental odontogenic cyst are there?

Answer 8

Dentigerous cyst (eruption cyst)
Odontogenic keratocyst
Lateral periodontal cyst

Question 9

What types of inflammatory odontogenic cyst are there?

Answer 9

Radicular cyst (residual)
Paradental cyst
Buccal bifurcation cyst

Question 10

What types of non-odontogenic cyst are there?

Answer 10

Nasopalatine duct cyst
Nasiolabal cyst
Globulomaxillary cyst
Median cyst

Question 11

What types of non-epithelial cyst are there?

Answer 11

Solitary bone cyst
Aneurysmal cyst

Question 12

What are odontogenic cysts?

Answer 12

Occur in tooth-bearing areas
Most common cause of bony swelling
Lined with epithelium

Question 13

What are the sources of odontogenic cysts?

Answer 13

Rests of Malassez
Rests of Serres
Remnants of reduced enamel epithelium

Question 14

What is a radicular cyst?

Answer 14

An inflammatory odontogenic cyst
Always associated with a non-vital tooth
Chronic inflammation from apex of tooth

Question 15

What are the radiographic features of a radicular cyst?

Answer 15

Well defined
Corticated margin continuous with lamina dura of non-vital tooth
Displacement of adjacent structures

Question 16

Describe the histology of a radicular cyst?

Answer 16

Often incomplete epithelial lining
Connective tissue capsule
Inflammation within capsule

Question 17

Describe the way in which a radicular cyst can form from a granuloma?

Answer 17

Rests of Malassez proliferate into PA granuloma

Proliferating epithelium has central necrosis OR

Epithelium surrounds fluid area

Continued growth occurs due to semi-permiable wall and cytokine mediated growth

Question 18

What is a residual cyst?

Answer 18

A cyst persisting after the loss of a tooth. Appears as longitudinal bony defect.

Question 19

What is a lateral radicular cyst

Answer 19

A radicular cyst associated with an accessory canal.

Located at the side of the tooth rather than the apex.

Question 20

What are inflammatory collateral cysts?

Answer 20

Inflammatory odontogenic cysts, associated with a vital tooth.

Further differentiation into paradental cyst, and buccal bifurcation cyst.

Question 21

What is a dentigerous cyst?

Answer 21

Developmental odontogenic cyst, associated with crown of unerupted tooth.

Question 22

Give four histological signs of a radicular cyst?

Answer 22

Variable inflammation
Cholesterol clefts
Mucous metaplasia
Hyaline/rushton bodies

Question 23

How would you differentiate between an enlarged follicle an a dentigerous cyst?

Answer 23

Consider cyst if follicular space 5mm or more.

Normal follicular space is 2-3mm, and if this exceeds 10mm then assume its a cyst.

Question 24

What is an eruption cyst?

Answer 24

A variant of dentigerous cyst, contained within the soft tissue.

Associated with an erupting tooth, and found more commonly in the incisors.

Question 25

What is an odontogenic keratocyst?

Answer 25

Developmental odontogenic cyst, with no specific relationship to teeth.

Question 26

What is basal cell naevus syndrome?

Answer 26

Multiple odontogenic keratocysts Multiple basal cell carcinomas Calcification of inter cranial dura mater

Question 27

What is a mucous retention cyst?

Answer 27

Benign self-limiting lesions, that originate from the accumulation of fluids inside the sinus membrane

Question 28

Give three examples of non-odontogenic cyst?

Answer 28

Nasopalatine duct cyst Solitary bone cyst Aneurysmal bone cyst

Question 29

If a cyst presents below the IAN canal of the mandible, what is the cyst more likely to be?

Answer 29

A non-odontogenic cyst

Question 30

How does a nasopalatine duct cyst present?

Answer 30

Circuluar radiolucency in the duct Arrises from the nasopalatine duct, and occurs in the anterior maxilla.

Question 31

What radiographic views may be useful when investigating a nasopalatine duct cyst?

Answer 31

PA Standard maxillary occlusal CBCT if planning surgery

Question 32

What are the radiographic findings of a nasopalatine duct cyst?

Answer 32

Corticated radiolusency between/over roots of central incisors Often uniocular May appear heart shaped due to superimposition of nasal spine

Question 33

What anatomical feature may be confused with a nasopalatine duct cyst?

Answer 33

The incisive fossa Sizes 6-10mm in diameter monitor 10mm+ suspect cyst

Question 34

What is a solitary bone cyst?

Answer 34

Non-odontogenic cyst without an epithelial lining Can be simple, tarumatic, or haemorrhagic Can occur in association with other bone pathology

Question 35

How do solitary bone cysts present?

Answer 35

Usually asymptomatic Rarely pain and swelling Radiographically: - Majority in premolar/molar region of mandible - Variable definition and cortication - May have scalloped margins - May project up between roots of adjacent teeth

Question 36

What is a Stafne cavity?

Answer 36

Depression in the bone, containing salivary of fatty tissue. Most common on angle or posterior body of mandible. Typically well defined, corticated, and asymptomatic.

Question 37

What methods are there for obtaining a sample for histopath?

Answer 37

Aspiration biopsy (drain contents) Incisional biopsy (partial removal) Excisional biopsy (complete removal)

Question 38

What are the two main treatment options for cysts?

Answer 38

Enucleation (All of cyst is removed) Marsupialisation (Create window, remove contents, and suture cyst wall to epithelium)

Question 39

What are the advantages of enucleation?

Answer 39

Whole lining can be pathologically examined Primary closure Little aftercare is needed

Question 40

What are the contraindications of enucleation?

Answer 40

Risk of mandibular fracture with large cysts May wish to preserve tooth Old age/ill health

Question 41

What are the potential risks of enucleation?

Answer 41

Cavity may become infection Incomplete removal, leading to recurrance Damage to adjacent structures inc. teeth

Question 42

What are the indications for marsupialisation?

Answer 42

If enucleation would damage structures Difficult access to area May allow eruption of teeth Lower risk of jaw fracture

Question 43

What are the advantages of marsupialisation?

Answer 43

Simple to perform May spare vital structures

Question 44

What are the contraindications for marsupialisation?

Answer 44

Opening may close and cyst may reform Complete lining not available for histopath Difficult to keep clean Requires obturator to keep open Long time for bony infil

Question 45

What are the differential diagnosis for non-cystic radiolucencies?

Answer 45

Odotogenic tumours Giant cell lesions FCO lesions Radiolucent non-odontogenic tumours

Question 46

What is the management of a suspected cyst in general practice?

Answer 46

Referral Initial consultation Special investigation Biopsy Diagnosis Tx: - Enucleation - Marsupialisation - Surgical resection