17. Non-odontogenic cysts Flashcards
What is an example of non-odontogenic cysts?
A non-odontogenic cyst is a cyst that is not related to the epithelial residues of the tooth forming organ.
What are 2 examples of epithelialised non-odontogenic bone cysts?
Nasopalatine cyst
Nasolabial cyst
What is nasopalatine cyst origin?
Nasopalatine duct epithelium embryonic vestigial residues
What is nasopalatine cyst in soft tissue called?
Papilla palatine cyst
What is the symptoms of nasopalatine cyst?
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
What is the lining of nasopalatine cyst?
Stratified squamous
Pseudostratified ciliated cuboidal columnar cells
Mucous
Contains connective tissue with some mucous glands, chronic cell inflammatory infiltration, neurovascular bundles
What is the origin of a nasolabial cyst?
Nasolacrimal duct epithelial embryonic residues
Where does a nasolabial cyst occur?
Below ala of nose
In soft tissue of the upper lip
Occasionally bilateral
What is the symptoms of nasolabial cyst?
Swelling, sometimes pain
Difficulty breathing
What does the radiograph show for nasolabial cyst?
Increased radiolucency at apex of incisor teeth
What is the histology of nasolabial cyst?
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
What is a solitary bone cyst?
Often found in mandible molar/premolar region
Bone expansion in 25%
Children and adolescents
Single lesion
No acute or prolonged inflammation
What is the origin of solitary bone cyst?
Trauma with medullary haemorrhage.
Clot liquefaction.
What does radiograph show for solitary bone cyst?
Scalloping between teeth and remote areas too
What is the histology of solitary bone cyst?
Contains air, gas, serous fluid, blood
Bony walls covered by loose fibrous vascular tissue, haemosiderin, multinucleated giant cells
No lining
What is an aneurysmal bone cyst?
Found in posterior mandible, rarer in maxilla
Primary lesions or secondary to fibro-osseous lesions and giant cell granuloma
What does the lesion in aneurysmal bone cyst look like?
Firm swelling, expansile, balloon cortex, can be painful
What is aneurysmal bone cyst due to?
Maybe due to haemodynamic disturbance in the medullary bone
What does the radiograph show for aneursymal bone cyst?
Uni or multiocular radiolucency
What is the histology of aneurysmal bone cyst?
Numerous no-endothelium lined blood filled spaces
Acellular fibrous tissue
Haemorrhage
Haemosiderin
Multinucleated giant cells
No lining
What is Stafne’s idiopathic bone cavity?
Development anomaly in mandible between angle of mandible and premolar, lingual side below ID canal
No symptoms could be bilateral
Not a cyst
What does stafne’s idiopathic cavity look like?
Round, oval, well demarcated defect
Saucer shaped 3D
What does stafne’s idiopathic bone cavity contain?
Ectopic submandibular salivary gland tissue
Could confirm with sialograph
What is mucous extravasation cyst?
Extravasation of mucus due to ruptured duct
Mostly lower lip
Bluish/translucent submucosal swelling
What is the histology of mucous extravasation cyst?
No epithelium lining
Chronic inflammatory cells
Foam cells
Granulation tissue wall
Mucin filled cavity
What is mucous retention cyst?
Often due to blocked/partially obstructed duct
Almost never in lower lip
What is the histology of mucous retention cyst?
Lined by epithelium
Lack of inflammation
Diilatation of duct
What is a lymphoepithelial cyst?
Occurs when you get lymphoid tissue trapped in the oral mucosa and cyst formation
Where does lymphoepithelial cysts occur?
Parotid gland
Lateral neck
Floor of mouth
What is the histology of lymphoepithelial cyst?
Stratified squamous or pseudostratified epithelium
Entrapped by lymphoid tissue
Contains serous fluid with desquamated epithelium and lymphocytes
Where do dermoid and epidermoid cysts occcur?
Many sites, including Floor of mouth
Intraoral or submental in midline
What is the cause for dermoid and epidermoid cysts?
Epithelium enclavement during fusion of the mandibular and hyoid branchial arches
What is the histology of dermoid and epidermoid cysts?
Orthokeratinised
Stratified squamous epithelium
With keratin debris in the lumen
What does a dermoid cyst contain?
Skin appendages- hair follicles, sebaceous glands, sweat glands, erector pili muscles
How does dermoid and epidermoid cysts occur in other locations?
Traumatic implantation of epithelium deep in tissues
What is an antral cyst?
Pseudocyst.
Soft tissue elevation from floor of the maxillary sinus
What is found in an antral cyst?
Accumulation of inflammatory exudate, no mucin
What is the radiographic finding of antral cyst?
Dome shaped radiopacity
Where do antral cysts occur most?
Anterior-lateral wall in sinus
What is the symptoms of antral cyst?
Pain, swelling, pus discharge
What is the reason for antral cysts occuring?
Most happen after surgery due to epithelial antral lining rests being left behind in surgery, and forming cysts.
What is a branchial cyst and where does it ocur?
Developmental cyst
Epithelium entrapped in cervical lymph node
Where does a branchial cyst occur?
Angle of mandible and anterior sternomastoid muscle border
What are the symptoms of branchial cysts?
Asymptomatic
Movable mass
Clear with transillumination
What does a branchial cyst look like?
Similar site and appearance to metastatic squamous cell carcinoma from primary oropharyngeal tumour
How do you tell the difference between SCC and branchial cyst?
If the person is below 40-45, likely to be branchial cleft cyst.
If they are over 45-50, likely to be SCC.
What is the cause of a thyroglossal duct cyst?
Developmental lesion from embryonic thyroglossal duct
Where does thyroglossal duct occur?
From foramen caecum in midline of tongue, to thyroid gland
Most cysts are near the hyoid bone
What is the lining of thryoglossal duct?
Stratified squamous ciliated columnar epithelium
What does the wall of thryoglossal duct contain?
Thyroid tissue
Lymphoid tissue
Mucous glands
What is the symptoms of thyroglossal duct cyst?
Dysphagia
