Cysts

Question 1

What is a cyst?

Answer 1

A pathological cavity containing fluid, semi-fluid or gaseous contents
Not been created by accumulation of pus

Can be epithelial or non epithelial

Question 2

What are the subdivisions of epithelial cysts

Answer 2

Odontogenic (inflammatory/ developmental)
Non odontogenic

Question 3

What are the two main types of odontogenic inflammatory cysts?

Answer 3

Radicular cysts
Inflammatory collateral cysts

Question 4

What are the main features of a radicular cyst?

Answer 4

Inflammation causing proliferation of epithelium (rests of malessez - originates from hertwigs root sheath, dental follicle)
Associated with non vital tooth
Could be apical/ lateral/ residual

Question 5

What is a residual cyst?

Answer 5

A radicular cyst remaining in the jaw after extraction of affected tooth

Question 6

What is the treatment for a radicular cyst?

Answer 6

Simple enucleation and removal of associated tooth

Question 7

What are the histological features of a radicular cyst?

Answer 7

Regular lining of non keratinised squamous epithelium
Vascular capsule
Inflammatory infiltrate

Question 8

What is the radiographic presentation of a radicular cyst?

Answer 8

Round radiolucency at root apex
Unilocular, well defined
Uniform radiolucency

Question 9

What is an inflammatory collateral cyst?

Answer 9

Occurs on the lateral aspect of a partially erupted, vital tooth
(M3Ms the inflammatory stimulus is pericoronitis)

Question 10

What type of cysts occurs on the buccal aspect of erupting fist molars in children?

Answer 10

Mandibular buccal bifurcation cysts

Question 11

What type of cyst is a dentigerous cyst?

Answer 11

A developmental cyst

Question 12

What are the radio graphic features of a dentigerous cyst?

Answer 12

Round, unilocular, well defined, uniform radiolucency
Attached to crown of unerupted tooth

Question 13

What is the lining of a dentigerous cyst derived from?

Answer 13

Reduced enamel epithelium

Question 14

What are the histopathology features of a dentigerous cyst?

Answer 14

Thin regular layer of non keratinised stratified squamous epithelium

Question 15

What a re the main features of a dentigerous cyst?

Answer 15

Mostly with impacted mandibular third molars
Embraces all/ part of the crown of an unerupted tooth (attached at CEJ)

Question 16

What is the treatment of a dentigerous cyst?

Answer 16

Cyst enucleation/ marsupialisation if large

Question 17

What is an eruption cyst?

Answer 17

A type of developmental cyst overlying an erupting tooth
Most commonly deciduous incisors/ FPMs

Question 18

What is an odontogenic keratocyst?

Answer 18

A type of developmental cyst which arises from the cell rests of serres (remnants of dental lamina)
Has an unusual growth pattern with high risk of recurrence
Enlarges in anterior posterior direction

Question 19

Where are odontogenic keratocysts most common?

Answer 19

In the mandible, especially third molar region

Question 20

What is the radio graphic presentation of an odontogenic keratocyst?

Answer 20

Oval
Well defines, uniform
Uni or multi locular

Question 21

What are the histopathological features of an odontogenic keratocyst?

Answer 21

Thin connective tissue wall
Lined by thin, folded parakeratinised stratified squamous epithelium

Question 22

What is basal cell naevus syndrome?

Answer 22

Autosomal dominant condition which can result in multiple odontogenic keratocysts (and increased risk of basal cell carcinoma)

Question 23

What is the difference between an orthokeratinised odontogenic cyst and an odontogenic keratocyst?

Answer 23

Orthokeratinised odontogenic cysts rarely recur, have no occurrence with basal cell naevus syndrome and have distinct flattened basal cell layer (histologically)

Question 24

What is a lateral periodontal cyst?

Answer 24

A rare odontogenic developmental cyst which is associated with canine/ premolar region in mandible and vital tooth
Treated with simple enucleation

Question 25

What are gingival cysts?

Answer 25

Cysts derived from rests of serres (dental lamina) Common in infants (bohns nodules) appearing as white/ yellow nodules on edentulous mucosa. These cysts naturally degenerate. Can occur in adults as <1cm pink swellings on attached gingiva

Question 26

What are examples of non odontogenic cysts?

Answer 26

Nasolabial cyst Nasopalatine cyst

Question 27

What is a nasopalatine cyst?

Answer 27

Most common non odontogenic cyst Originates from epithelial remnants of nano palatine duct Slowly enlarging swelling in anterior region of midline of palate Appears as a heart shape radiographically

Question 28

What is the lining of nasopalatine cyst?

Answer 28

Stratified squamous and respiratory epithelium

Question 29

What are examples of non epithelial cysts of the jaw?

Answer 29

Solitary bone cyst Aneurysmal bone cyst Stafnes idiopathic bone cavity

Question 30

What is a solitary bone cyst?

Answer 30

Aetiology is unknown A simple/ haemorrhagic/ traumatic bone cyst Radiographic presentation - irregular outline, moderately well defined, scalloping a prominent feature Surgical exploration allows rapidly healing and resolving

Question 31

What is stafnes idiopathic bone cavity?

Answer 31

Developmental anomaly of the mandible Usually at angle of mandible Below inferior dental canal Saucer shape depression on lingual aspect, usually from enlarged sub mandibular gland

Question 32

What is enucleation?

Answer 32

Removal of entire cyst lining and contents Useful for radicular/ residual, dentigerous cysts and keratocysts

Question 33

Why is enucleation not a treatment option for ameloblastomas?

Answer 33

Ameloblastomas have high recurrence rates due to thin, fragile lining. Therefore 1cm sound tissue must also be removed - in the mandible this is too large

Question 34

What are complications of enucleation?

Answer 34

Damage to IAN OAC Pathological fracture of mandible Risk of recurrence

Question 35

What is marsupilisation?

Answer 35

Shrinking of the cyst by allowing drainage Useful for large cysts, karatocyst, dentigerous cyst

Question 36

What are complications of marsupilisation?

Answer 36

Needs further surgical treatment for removal Long treatment before completion (1 year) Chance of re infection Uncomfortable

Question 37

What is the size of a cyst v granuloma?

Answer 37

Granuloma <10mm Cyst >10mm

Question 38

Why would marsupilisation be the preferred treatment option over enucleation?

Answer 38

If enucleation would damage surrounding structures If difficult access for enucleation To allow eruption of teeth If enucleation may risk pathological jaw fracture

Question 39

What can be utilised to keep marsupilisation window open?

Answer 39

An obturator

Question 40

What can be utilised to keep marsupilisation window clean?

Answer 40

Chlorhexidine mouthwash

Question 41

What is an example of an odontogenic tumour?

Answer 41

Ameloblastoma Ameloblastic fibroma

Question 42

What are examples of giant cell lesions in the jaw?

Answer 42

Peripheral and central giant cell granuloma Cherubism

Question 43

What are examples of radiolucent non odontogenic tumours which may be found in the jaw?

Answer 43

Chondroma Osteosarcoma Squamous cell carcinoma Central haemangioma