cysts: surgical management

Question 1

define cyst

Answer 1

A pathological cavity containing fluid or gas, and which is NOT created by the accumulation of pus.

Most cysts are lined by epithelium.

Question 2

what are odontogenic cysts?

Answer 2

cysts whereby the epithelial lining is derived from remnants of the tooth forming tissue.

They are subdivided into inflammatory and
developmental.

Question 3

what are non-odontogenic cysts?

Answer 3

Cysts whose epithelial lining is derived from sources other than tooth forming tissue

Question 4

describe the mechanism of cystic growth:

Answer 4

Inflammation causes epithelium proliferation

the cells in the cyst centrally breakdown.

this Increased osmotic pressure draws the water inwards.

Bone resorption occurs (due to the release of collagenase and prostaglandins by fibroblasts, osteoclasts and stimulating factors.)

Question 5

what are the key features of cysts?

Answer 5

-Form sharply defined radio-lucencies

• their fluid may be aspirated, and some thin-walled cysts can be transilluminated (difficult intra-orally)

Slow growing, displace rather than resorb teeth

• Symptomless unless infected and often incidental findings on radiographs
• Rarely large enough to cause pathological fractures
• Form compressible and fluctuant swellings if extending into the soft tissues

-Appear bluish when close to the mucosal surface

Question 6

what is are radicular cysts?

Answer 6

Commonest of all odontogenic cysts, account for over 50% of jaw cysts2. They rarely occur before 10 years of age and are due to chronic inflammation in the peri-radicular tissues resulting in a periapical granuloma stimulating the epithelium rests of Malassez.
Following this there is central degeneration and necrosis which causes the formation of a cavity. This cavity is lined by epithelium.
As described above, cyst expansion is then via hydrostatic pressure as debris accumulates centrally.
Radicular cysts are always associated with a non-vital tooth, and this is an important diagnostically.

Question 7

what are radicular cysts always associated with?

Answer 7

with a non-vital tooth, and this is an important diagnostic factor

Question 8

what is the tx of radicular cysts?

Answer 8

Enucleation

Question 9

what are Residual Cysts?

Answer 9

These are radicular cysts which remain in situ after the tooth/teeth have been removed.

the histological features are very similar, but the source of the inflammation has been <removed>
and therefore the wall of a residual cyst may mature = become relatively uninflamed with a thin and irregular lining.</removed>

Question 10

what is the tx of residual cysts ?

Answer 10

enucleation

Question 11

what structure must you consider if a sectional OPT shows a significant residual cyst in the left mandible ?

Answer 11

mental nerve

Question 12

what are lateral periodontal cysts?

Answer 12

cysts associated with the later surface of a tooth root.

usually an incidental radiographic finding

most common in canine and premolar region.

radiographically you would see a unilocular radiolucency lateral to the tooth

the adj teeth are usually vital.

Question 13

are lateral periodontal teeth cysts related to vital or non vital adj teeth?

Answer 13

usually vital

Question 14

what is the tx of lateral periodontal cysts?

Answer 14

enucleation

Question 15

what is the most common developmental odontogenic cyst?

Answer 15

dentigerous cyst

accounts for 20% of all ondontogenic cysts

60% of developmental cysts

Question 16

which teeth are dentigerous cysts associated with?

Answer 16

mandibular 3rd molars

Question 17

what are dentigerous cysts?

Answer 17

cysts that enclose the crown of the unerupted tooth

lined by epithelium

derived from reduced enamel epithelium

Question 18

what might dentigerous cysts do?

Answer 18

displace impacted tooth and prevents its eruption.

Question 19

what is the tx of dentigerous cysts?

Answer 19

-Marsupialization
-enucleation + extraction of the tooth

Question 20

what are eruption cysts?

Answer 20

occur on the mucosa of a tooth prior to eruption and are most frequently found overlying deciduous incisors or first permanent molars

(superficial dentigerous cyst)

Question 21

what happens to most eruption cysts?

Answer 21

burst spontaneously

rarely cause pain/become infected

Question 22

what is the tx of eruption cysts?

Answer 22

Marsupialization

=the underlying tooth will usually erupt spontaneously

Question 23

what are odontogenic keratocysts ?

Answer 23

A cyst arising from remnants of the dental lamina, with high recurrence rate, permeative growth pattern, presence of satellite cysts, and mutations in the PTCH tumour suppressor gene.

Question 24

in who do odontogenic keratocyts occur?

Answer 24

Occur in patients over a wide age range
More common in the mandible, and often asymptomatic unless swelling.
They extend through the path of least resistance and often through the ramus and body of the mandible prior to causing obvious bony expansion.
Recurrence rate is between 25-60%.

Question 25

what can we see radiographically in odontogenic keratocyts

Answer 25

Well defined, often with a rounded or scalloped margin.
Can be unilocular or multilocular
May envelope a tooth and therefore be difficult to distinguish between a dentigerous cyst. May displace adjacent teeth and inferior alveolar nerve canal.

Question 26

what might odontogenic keratocyts do?

Answer 26

May displace adjacent teeth and inferior alveolar nerve canal.

Question 27

Multiple OKC’s in the same patient are one of the consistent features of ?

Answer 27

Gorlin Goltz Syndrome or Basal Cell Naevus.

This comprises of a triad of multiple basal cell naevi, odontogenic keratocysts of the jaws and skeletal anomalies.

Question 28

Characteristic Features of Gorlin Goltz Syndrome or Basal Cell Naevus.

Answer 28

• Frontal and parietal bossing & broad nasal root
• Multiple OKCs of the jaws
• Multiple naevoid BCCs of the skin
• Skeletal anomalies (bifid ribs and abnormalities of the vertebrae)
• Intra-cranial anomalies (e.g., calcification of falx cerebri and abnormally shaped sella turcica)
• CLP in ~5%

Question 29

tx of odontogenic keratocyts?

Answer 29

Enucleation +/- resection

(Recurrence rates are high
Long term follow-up and regular imaging)

Question 30

what are Calcifying Epithelial Odontogenic Tumours?

Answer 30

Rare

often mistaken as a carcinoma on histology.

Presents at any age, but commonly 4th decade
Posterior body of the mandible/angle

has ‘bizarre’ features.

Appears cystic but with flecks of calcifications.

Roots of teeth are often eroded in association with the lesion.

poorly defined margins.

Locally invasive but not metastasise.

Question 31

tx of Calcifying Epithelial Odontogenic Tumour
‘Pindborg Tumour’ or ‘Ghost Cell’

Answer 31

Enucleation

Question 32

what are stafne bone cysts?

Answer 32

Usually, asymptomatic

Radiographically shows as a radiolucency located under the inferior alveolar nerve canal.

Question 33

stafne bone cyst tx?

Answer 33

conservative

Question 34

what are Aneurysmal Bone Cysts?

Answer 34

Non-epithelial lined cyst-like lesion
Can be aggressive

Typically contains blood filled spaces with giant cells and fibroblasts

Mandible is more common than maxilla and are benign.

Question 35

what are Solitary Bone Cysts?

Answer 35

usually incidental finding Non-epithelial lined (pseudocyst)

Usually vital teeth

Aetiology uncertain

more common in young adults

Sometimes contains blood-stained serous fluids or gas

Question 36

management of solitary bone cysts ?

Answer 36

curettage/enucleation

Question 37

what are Naso-palatine Duct Cysts?

Answer 37

Common

located in the nasopalatine duct

occurs due to epithelial remnants of the nasopalatine duct.

More common in males

between 20 and 60 years.

Often an incidental finding.

Question 38

tx of nasopalatine cysts ?

Answer 38

Enucleation

but recurrence can be high due to poor surgical technique

Question 39

how do we investigate cysts

Answer 39

take a history
examination

plain film radiographs are useful, howeve cone-beam CT is a more appropriate image giving detailed information.

Question 40

what special tests do we conduct for diagnosing ?

Answer 40

vitality testing
biopsy

Question 41

what are some definitive tx options for cysts

Answer 41

Conservative Decompression
Enucleation
Enucleation & curettage Resection +/- reconstruction

Question 42

what is Active Clinical monitoring?

Answer 42

“Wait and watch”
If the patient is un-fit for surgery, or significant risk of complications Dependent upon the diagnosis

Question 43

what is Decompression?

Answer 43

Marsupialization – opens a window into the cavity allowing the pressure to reduce and therefore reduce the size of the cyst to then be able to enucleate.
Advantages:
Simple, preserves vital structures including teeth.
Disadvantages:
Patient compliance (OH) can be time consuming and requires a second procedure.

Question 44

what is Enucleation?

Answer 44

the entire specimen is removed and is generally curative and allowing pathological examination of the specimen.

technically challenging and risks damage to vital structures including the risk of a fracture if a significant sized cyst.

If the enucleation is incomplete this can lead to recurrence of the lesion.

This is more common when the cyst has perforated through the alveolar cortex and the lining is adherent to adjacent soft tissues.

Question 45

what is Resection +/- reconstruction?

Answer 45

Excision of the lesion with a margin of ‘clinically’ normal looking tissue.

can be challenging, and the aim is curative.

problems:
mainly with the defect left after resection which may well require reconstruction with a free-flap or graft depending upon the location and size of defect.