17. Non-odontogenic cysts

Question 1

What is an example of non-odontogenic cysts?

Answer 1

A non-odontogenic cyst is a cyst that is not related to the epithelial residues of the tooth forming organ.

Question 2

What are 2 examples of epithelialised non-odontogenic bone cysts?

Answer 2

Nasopalatine cyst
Nasolabial cyst

Question 3

What is nasopalatine cyst origin?

Answer 3

Nasopalatine duct epithelium embryonic vestigial residues

Question 4

What is nasopalatine cyst in soft tissue called?

Answer 4

Papilla palatine cyst

Question 5

What is the symptoms of nasopalatine cyst?

Answer 5

Asymptomatic or pain on pressure
Sclerotic rim
Round/ovoid
Heart shaped
DD from normal incisive fossa
If more than 6mm likely to be a cyst
Salty taste- mucoid
Foul taste- purulent

Question 6

What is the lining of nasopalatine cyst?

Answer 6

Stratified squamous
Pseudostratified ciliated cuboidal columnar cells
Mucous
Contains connective tissue with some mucous glands, chronic cell inflammatory infiltration, neurovascular bundles

Question 7

What is the origin of a nasolabial cyst?

Answer 7

Nasolacrimal duct epithelial embryonic residues

Question 8

Where does a nasolabial cyst occur?

Answer 8

Below ala of nose
In soft tissue of the upper lip
Occasionally bilateral

Question 9

What is the symptoms of nasolabial cyst?

Answer 9

Swelling, sometimes pain
Difficulty breathing

Question 10

What does the radiograph show for nasolabial cyst?

Answer 10

Increased radiolucency at apex of incisor teeth

Question 11

What is the histology of nasolabial cyst?

Answer 11

Ciliated or non-ciliated
Pseudostratified ciliated columnar epithelium and goblet cells
Cuboidal epithelium
Squamous metaplasia in 2-3 layers
Cyst walls contains relatively acellular connective tissue

Question 12

What is a solitary bone cyst?

Answer 12

Often found in mandible molar/premolar region
Bone expansion in 25%
Children and adolescents
Single lesion
No acute or prolonged inflammation

Question 13

What is the origin of solitary bone cyst?

Answer 13

Trauma with medullary haemorrhage.
Clot liquefaction.

Question 14

What does radiograph show for solitary bone cyst?

Answer 14

Scalloping between teeth and remote areas too

Question 15

What is the histology of solitary bone cyst?

Answer 15

Contains air, gas, serous fluid, blood
Bony walls covered by loose fibrous vascular tissue, haemosiderin, multinucleated giant cells
No lining

Question 16

What is an aneurysmal bone cyst?

Answer 16

Found in posterior mandible, rarer in maxilla
Primary lesions or secondary to fibro-osseous lesions and giant cell granuloma

Question 17

What does the lesion in aneurysmal bone cyst look like?

Answer 17

Firm swelling, expansile, balloon cortex, can be painful

Question 18

What is aneurysmal bone cyst due to?

Answer 18

Maybe due to haemodynamic disturbance in the medullary bone

Question 19

What does the radiograph show for aneursymal bone cyst?

Answer 19

Uni or multiocular radiolucency

Question 20

What is the histology of aneurysmal bone cyst?

Answer 20

Numerous no-endothelium lined blood filled spaces
Acellular fibrous tissue
Haemorrhage
Haemosiderin
Multinucleated giant cells
No lining

Question 21

What is Stafne’s idiopathic bone cavity?

Answer 21

Development anomaly in mandible between angle of mandible and premolar, lingual side below ID canal
No symptoms could be bilateral
Not a cyst

Question 22

What does stafne’s idiopathic cavity look like?

Answer 22

Round, oval, well demarcated defect
Saucer shaped 3D

Question 23

What does stafne’s idiopathic bone cavity contain?

Answer 23

Ectopic submandibular salivary gland tissue
Could confirm with sialograph

Question 24

What is mucous extravasation cyst?

Answer 24

Extravasation of mucus due to ruptured duct
Mostly lower lip
Bluish/translucent submucosal swelling

Question 25

What is the histology of mucous extravasation cyst?

Answer 25

No epithelium lining Chronic inflammatory cells Foam cells Granulation tissue wall Mucin filled cavity

Question 26

What is mucous retention cyst?

Answer 26

Often due to blocked/partially obstructed duct Almost never in lower lip

Question 27

What is the histology of mucous retention cyst?

Answer 27

Lined by epithelium Lack of inflammation Diilatation of duct

Question 28

What is a lymphoepithelial cyst?

Answer 28

Occurs when you get lymphoid tissue trapped in the oral mucosa and cyst formation

Question 29

Where does lymphoepithelial cysts occur?

Answer 29

Parotid gland Lateral neck Floor of mouth

Question 30

What is the histology of lymphoepithelial cyst?

Answer 30

Stratified squamous or pseudostratified epithelium Entrapped by lymphoid tissue Contains serous fluid with desquamated epithelium and lymphocytes

Question 31

Where do dermoid and epidermoid cysts occcur?

Answer 31

Many sites, including Floor of mouth Intraoral or submental in midline

Question 32

What is the cause for dermoid and epidermoid cysts?

Answer 32

Epithelium enclavement during fusion of the mandibular and hyoid branchial arches

Question 33

What is the histology of dermoid and epidermoid cysts?

Answer 33

Orthokeratinised Stratified squamous epithelium With keratin debris in the lumen

Question 34

What does a dermoid cyst contain?

Answer 34

Skin appendages- hair follicles, sebaceous glands, sweat glands, erector pili muscles

Question 35

How does dermoid and epidermoid cysts occur in other locations?

Answer 35

Traumatic implantation of epithelium deep in tissues

Question 36

What is an antral cyst?

Answer 36

Pseudocyst. Soft tissue elevation from floor of the maxillary sinus

Question 37

What is found in an antral cyst?

Answer 37

Accumulation of inflammatory exudate, no mucin

Question 38

What is the radiographic finding of antral cyst?

Answer 38

Dome shaped radiopacity

Question 39

Where do antral cysts occur most?

Answer 39

Anterior-lateral wall in sinus

Question 40

What is the symptoms of antral cyst?

Answer 40

Pain, swelling, pus discharge

Question 41

What is the reason for antral cysts occuring?

Answer 41

Most happen after surgery due to epithelial antral lining rests being left behind in surgery, and forming cysts.

Question 42

What is a branchial cyst and where does it ocur?

Answer 42

Developmental cyst Epithelium entrapped in cervical lymph node

Question 43

Where does a branchial cyst occur?

Answer 43

Angle of mandible and anterior sternomastoid muscle border

Question 44

What are the symptoms of branchial cysts?

Answer 44

Asymptomatic Movable mass Clear with transillumination

Question 45

What does a branchial cyst look like?

Answer 45

Similar site and appearance to metastatic squamous cell carcinoma from primary oropharyngeal tumour

Question 46

How do you tell the difference between SCC and branchial cyst?

Answer 46

If the person is below 40-45, likely to be branchial cleft cyst. If they are over 45-50, likely to be SCC.

Question 47

What is the cause of a thyroglossal duct cyst?

Answer 47

Developmental lesion from embryonic thyroglossal duct

Question 48

Where does thyroglossal duct occur?

Answer 48

From foramen caecum in midline of tongue, to thyroid gland Most cysts are near the hyoid bone

Question 49

What is the lining of thryoglossal duct?

Answer 49

Stratified squamous ciliated columnar epithelium

Question 50

What does the wall of thryoglossal duct contain?

Answer 50

Thyroid tissue Lymphoid tissue Mucous glands

Question 51

What is the symptoms of thyroglossal duct cyst?

Answer 51

Dysphagia