Surgical Management of Cysts

Question 1

Define a cyst

Answer 1

A pathological epithelial lined cavity within tissue that can be filled with fluid or gas (not created by the formation of pus)

Question 2

How are cysts classified?

Answer 2

Cysts are classified into:

Hard tissue cysts

Soft tissue cysts

Hard tissue cysts are further divided into:

Odontogenic cysts (arising from the tooth or tooth forming structures)

Non-odontogenic cysts (arising from the fusion of plates, processes or the premaxilla during embryological development of the face)

Non-epithelial lined cysts (present like cysts but are not truly cysts as they are not epithelial lined cavities)

Soft tissue cysts are further divided into:

Developmental cysts

Non-developmental cysts

Question 3

When a patient presents with a suspected cyst, in general what special investigations should be requested?

Answer 3

X-rays, plain film or CBCT

Referral for biopsy of the area

Vitality testing of associated teeth

Question 4

List some red flag symptoms in a patient who is suspected to have a cyst, that may indicate something more sinister (malignancy)

Answer 4

Altered sensation or neurological involvement, particularly of the ID nerve (numbness in the lip, chin or tongue)

Mobility of teeth with no evident underlying source e.g., periodontitis

Sudden onset of swelling

Question 5

List all the methods of management for a cyst

Answer 5

Conservative

Decompression (marsupalisation)

Enucleation

Enucleation and curettage

Resection + margin

Question 6

Describe the conservative approach to management of a cyst

Answer 6

Accept and adapt approach with a wait and watch policy

Used for patients with a small cyst, patients who are unfit for surgery or not keen on any surgical intervention

High risk of complications in the long-term

Need to ensure we have the correct diagnosis before committing to this approach to ensure the lesion is not suspicious or requires referral for further investigation

Question 7

Describe decompression

Answer 7

Also known as marsupialisation (a process by which we reduce the size of a cyst prior to enucleation to allow easier removal)

Achieved by opening up a window into the cyst cavity and keeping this window open for a specific period, to allow the cyst to reduce over time. This will occur because the pressure within the cavity will reduce as a result of the opening, causing the cyst to become very small and easy to remove without damaging adjacent structures

Patients will have to keep this window into cavity very clean to prevent infection

Question 8

List the advantages and disadvantages of the process of Marsupialisation

Answer 8

Advantages-
Simple management technique to treat cysts

Allows preservation of vital structures and teeth

Disadvantages-

Hygiene compliance required. Patient will have to keep this open window clean

Can be a lengthy procedure

Patient may require a 2nd procedure to complete the treatment

Question 9

Describe enucleation

Answer 9

Refers to the removal of a cyst in its entirety

Question 10

List the advantages and disadvantages of enucleation

Answer 10

Advantages-
Remove the entire specimen of the cyst

If done correctly, it is a curative management approach

Disadvantages-
Technically challenging, especially if the cyst is large and is located with great proximity to adjacent vital structures

Risk of damaging vital structures surrounding the cyst

Risk of pathological fractures (mandibular fracture etc.) with very large cysts during treatment

Question 11

Describe the process of curettage

Answer 11

The cyst cavity is opened up and the epithelial lining is debrided (curetted out). The cavity is then given a clean and washed out.

The cyst is removed through a process of enucleation and then sent to histopathology.

Question 12

Describe the process of resection and margin

Answer 12

Also known as a wide local excision

More commonly used for large or risky looking cysts

Involves excising the cystic lesion with a margin of clinically normal looking tissue to ensure the cyst is removed in its entirety

Give the greatest chances of curing the cyst

Question 13

Describe the advantages and disadvantages of the resection and margin management technique

Answer 13

Advantages-

Useful for larger or riskier looking cysts

Offer the best chance of curing the cyst as we need to ensure we have a good margin of normal tissue during cyst removal. More likely to remove the entirety of the cyst using this technique therefore.

Disadvantages-

Can leave the patient with a significant deformity, as the cysts are usually very extensive

Can pose reconstructive challenges following cyst removal, leaving a wide area to reconstruct

Question 14

Describe the mechanism of cyst growth

Answer 14

The presence of inflammation causes epithelium to proliferate and form an epithelial lined cavity.

The cells in the centre of this forming cyst will begin to break down. And there will be a change in the osmotic pressure (increases), causing water to be drawn inwards. This allows the cyst to expand and increase in size

A release of collagenase and prostaglandins by fibroblasts as well as osteoclast stimulating factors will result in bone resorption as the cyst expands

Question 15

Describe the key features of cysts

Answer 15

Pathological epithelial lined cavity that may be filled with gas or fluid

Well defined, corticated mostly unilocular radiolucencies on a radiograph

Grow slowly, displacing rather than resorbing teeth

Usually symptomless unless they become infected (in which case they will cause pain/swelling)

Bone often becomes thin in the region of the cysts, this allows the cyst to extend into soft tissues (expansion) to cause a fluctuant soft swelling. Appear bluish when they’re close to the surface/extend into soft tissues

Sometimes, if these areas are touched, it may feel like cracked egg shells (this is when the risk of infection is high)

Question 16

Describe the epidemiology of radicular cysts

Answer 16

Pathological epithelial lined cyst arising from the epithelial cell rests of Malassez within the PDL (in response to chronic inflammation at the apex)

Affect males>females

Affect maxilla>mandible (3:2)

50% of all cysts within the jaw are radicular cysts.

70% of all odontogenic cysts are radicular cysts.

Rare before 10 years of age, tend to affect individuals aged 20-60 years

Question 17

Describe the epidemiology of dentigerous cysts

Answer 17

Pathological epithelial lined cavity arising from fluid collection between the enamel follicle and enamel surface

Affects males>females (2x)

Uncommon in children, usually affects those 20-50 years

Commonly affects 8s, 4s and U3s

Question 18

Describe the management protocol for radicular cysts

Answer 18

If the cyst is small enough, we would treat the tooth with endodontics (RCT) and monitor.

But if they’re larger or a RCT is not possible, the cyst would need to be enucleated (removed in its entirety), to be sent to histopathology.

A primary closure should be undertaken following this to allow healing

Question 19

Under the microscope, what do radicular cysts consist of?

Answer 19

The epithelium lining consists of stratified squamous epithelium of varying thickness in these cysts and often the capsule that encompasses them will have a collagenous fibrous connective tissue.

Within these cysts, histologically we would see chronic inflammatory cells, plasma cells which are a response to the antigenic material from a bacteria leaking out of the tooth’s apex

Question 20

Describe the epidemiology of residual cysts

Answer 20

A radicular cyst which persists after extraction of offending tooth

Common in the elderly, especially those with edentulous jaws

Question 21

Describe the epidemiology of lateral periodontal cysts

Answer 21

A pathological epithelial lined cavity that arises from tooth forming tissues (dental lamina, follicle or epithelial cell rests of Malassez within the PDL- origin not well understood)

Rare

Commonly affects 3s/4s (canines/premolars)

Question 22

Describe the management protocol for lateral periodontal cysts

Answer 22

Enucleation

+/- XLA of adjacent teeth (only XLA’d if involved with the cyst in some way and causing the patient issues)

Question 23

What is the management protocol for dentigerous cysts?

Answer 23

Marsupialisation (where cysts are particularly large)

Enucleation + XLA of associated unerupted tooth

Question 24

Describe the features of odontogenic keratocysts

Answer 24

Pathological epithelial lined cavity arising from the dental lamina

Uncommon, 10% of all odontogenic cysts

High recurrence

Radiographically tend to present as multilocular, well defined, corticated radiolucencies with scalloped/rounded margins

Generally are low pressure cysts that extend in the path of least resistance

Often extend through the ramus and body of the mandible before causing expansion (therefore late clinical presentation)

Associated risk of ameloblastoma stimulation

May be associated with an unerupted tooth appearing similar to a dentigerous cyst

May displace adjacent teeth and ID canal

May damage adjacent teeth (root resorption)

Question 25

Describe the epidemiology of odontogenic keratocysts

Answer 25

Peak incidence at 20-30 years (but can be 50-70 years)

Most commonly affect the angle of the mandible (50% of all cases)

Question 26

Under a microscope, describe the features of an odontogenic keratocyst

Answer 26

Cyst lined by thin parakeratinised stratified squamous epithelium

Characteristic corrugated surface

Well defined basal cell layer (indicating non malignancy)

Connective tissue wall of cyst is not inflamed

Question 27

What is the management protocol for odontogenic keratocysts?

Answer 27

Enucleation + curettage (gold standard)

Can be frozen via cryotherapy followed by enucleation.

Can undergo marsupialisation followed by enucleation

Can use Carnoy’s solution to fix the tissues, killing the cystic cells, followed by enucleation (but this can pose issues for nerves and are often neurotoxic)

Question 28

Describe the epidemiology of ameloblastomas

Answer 28

Rare but most common neoplasm (benign)

Most commonly affects those aged 30-60 years

Rare in extremes of age

Affects mandible>maxilla

Affects posterior mandible>anterior mandible (ramus)

Question 29

Describe the radiographic presentation of ameloblastomas

Answer 29

Rounded, moderately well defined, corticated radiolucency

Typically multilocular but can be unilocular, presenting similarly to cysts

Honeycomb pattern where multilocular

Difficult to distinguish from other pathologies using imaging alone

Question 30

Describe the features of a calcifying epithelial odontogenic cyst

Answer 30

Also known as a Pindborg tumour

Variable behaviour (some argue they are not cysts but low grade tumours)

Sometimes mistaken as carcinomas on histological examination

Locally invasive but does not metastasise

Expansile lesion

Asymptomatic unless infected (in which case there will be swelling and pain)

Radiographically presents as radiolucent areas with poorly defined margins. Can have areas of calcification or odontomas within them.

Question 31

Describe the epidemiology of calcifying odontogenic cysts

Answer 31

Rare

Commonly affect those that around 40 years of age

Commonly affect the posterior body of the mandible

Question 32

What is the management protocol for calcifying odontogenic cysts?

Answer 32

Enucleation/excision of cyst with a small clear margin of normal tissue

Question 33

Describe the features of a Staphne’s idiopathic bone cavity and its management protocol

Answer 33

Non-epithelial lined odontogenic cyst.

Developmental inclusion of submandibular salivary gland tissue in the lingual aspect of the mandible.

Radiographically presents as a well defined corticated round unilocular radiolucency, usually situated below the ID canal and not associated with the crown of an unerupted tooth or the apex of a non-vital tooth

Conservative treatment (non-surgical, leave and monitor)

Question 34

Describe the features of an aneurysmal bone cyst

Answer 34

Non-epithelial lined odontogenic cyst

Benign, expands slowly, can be locally aggressive and capable of dysplastic change

Affects mandible>maxilla

Typically contains a blood filled space interspersed with giant cells and fibroblasts

High recurrence rate

Question 35

Under a microscope, describe the features of an aneurysmal bone cyst

Answer 35

Non-epithelial lined cavity which contains a blood filled space interspersed with giant cells and fibroblasts

Question 36

Describe the management protocol for aneurysmal bone cysts

Answer 36

Enucleation + curettage

Followed by sample to histopathology

Question 37

Describe the features of a solitary bone cyst

Answer 37

Non-epithelial lined odontogenic cyst

Also known as traumatic bone cyst or unicameral cyst

Can be associated with childhood trauma

Often affect young adults

Can contain blood stained serous fluid or gas

Radiographically presents as a well defined, corticated, unilocular radiolucency with scalloped margins that extend up to the roots of associated teeth

Often associated with vital teeth

Question 38

Describe the management protocol for solitary bone cysts

Answer 38

Enucleation + curettage

Followed by sample to histopathology

Question 39

Describe the features of a naso-palatine duct cyst

Answer 39

Most common, non-odontogenic hard tissue cyst arising from the epithelial remnants of the nasopalatine duct (fusion of hard tissues during embryological development of the face)

Can clinically present as a swelling on the palatal aspect behind the upper central incisors

Radiographically presents as a round/pear shaped well defined corticated unilocular radiolucency that appears associated with the upper central incisors (located in the midline, on the palatal aspect)

High recurrence (due to poor treatment technique)

Question 40

Describe the epidemiology of a nasopalatine duct cyst

Answer 40

Most common non-odontogenic hard tissue cyst

Commonly affects those aged 20-60 years

Affects males>females

Located in the maxilla behind upper central incisors

Question 41

Under a microscope, describe the features of a nasopalatine duct cyst

Answer 41

Round/pear shaped cavity lined with stratified squamous and ciliated columnar epithelial cells

Question 42

Describe the management protocol for nasopalatine duct cysts

Answer 42

Enucleation