Nasolabial cyst

Nasolabial cyst

-Nasolaial cyst is a rare develpmental cyst arises in the soft tissue of upper lip lateral to midline, just below the ala of nose.

Etiology & pathogenesis,

There are 2 theories: the first theory considered nasolabial cyst to arise from remnants of epithelium at the site of fusion of the maxillary, medial nasal & lateral nasal processes.It is now suggested that the second theory is the most propable theory which consider nasolabial cyst to arise from remnants of misplaced epithelium of nasolacrimal duct.

Clinically,

-Female to male ratio is 4:1 .

-Nasolabial cyst appears as a swelling over canina region in the mucobuccal fold of the upper lip bellow ala of the nose .

-Because the cyst is asoft tissue cyst so there is not radiographic picture for this cyst.

Histopathological features,
Lining is pseudostratifies columnar epithelium ,mucous cells and cilia may be found,and inflammation may present if the cyst is secondary inflammed,

Treatment,

complete surgical excision.

N.B:

Nasolabial cyst is also known as nasoalveolar cyst ,klestadt cyst but because no bone is involved, its former name, nasoalveolar cyst, is inappropriate.

Nasopalatine duct cyst.

*Non odontogenic cysts*
1)Nasopalatine duct cyst.

-It's the commonest of nonodontogenic cysts,also known as incisive canal cyst and may be seen in the palatal soft tissue and so known as cyst of palatine papilla.

-Median palatine cyst (median cyst of the maxilla) may represent a posteriory displaced naso- palatine duct cyst.

-Nasopalatine ,incisive canal cyst ,cyst of palatine papilla and median alveolar cyst are all variants of the same lesion varying in position.

Etiology & pathogenesis,
-It is a developmental cyst arises from remnants of nasopalatine duct which connects oral and nasal cavities in the embryo, trauma or infection may be the cause that stimulate cystic degeneration.

-The cyst occurs anywhere along the duct's course which runs from the posterior palatal midline to the soft tissue of palatine papilla (incisive papilla), cyst in posterior palatine midline termed median palatine cyst and those formed in incisive papilla termed cyst of palatine papilla and all are considered nasopalatine duct cyst.

For further information about location and morphology of nasopalatine duct,follow or download this link,
http://archotol.ama-assn.org/cgi/reprint/126/6/741.pdf

Clinical features,
-Males are more affected.
-Many lesions are asymptomatic and discovered on routine radiographic examination , but may present as a swelling in soft tissue palatine papilla or may in midline of palate.

-Such lesions may discharge into the mouth through a sinus with a salty taste.

Radiographic picture,

-Well-defined round or ovoid or heart shape radiolucency at midline or may displace to one side.

-Anterior nasal spine superimposed on the lucent area giving the appearance of heart shape radiolucency.

-Diameter of nasopalatine cyst is in the range from 6mm to 6cm, so small cysts are difficult to be distinguished from incisive foramen which is of normal size from 6 to 7 mm in diameter.

-In rare instances , a nasopalatine duct cyst may develop in the soft tissues of the Incisive papilla area without anybony involvement. Such lesions often are called cysts of the incisive papilla . These cysts frequently demonstrate bluish discoloration as a result of the fluid content in the cyst lumen .

Histopathological features,

-The epithelial lining of nasopalatine duct cysts is highly variable, it may be stratified squamous epithelium or pseudostratifies ciliated columnar epithelium and less frequently simple columnar or cuboidal epithelium.

-Cyst arises in the superior aspect of the canal near nasal cavity is more likely to be respiratory epithelium (pseudostratified ciliated columnar epithelium) and cysts arising in the inferior position near the oral cavity are more likely to exhibit stratified squamous epithelium.
-Mucous secreting cells may be present and connective tissue wall also contains small arteries and nerve tissue,also an inflammatory response may be noted in the cyst wall

Simple cuboidal lining

Pseudo stratified columnar and stratified squamous

Show inflammation

Arteries & nerves

Treatment,

Surgical enucleation without recurrence.