The nasopalatine duct cyst is a distinct clinicopathological entity and is the commonest of the non-odontogenic cysts. It is a developmental lesion thought to arise from epithelial remnants of the nasopalatine duct which connects the oral and nasal cavities in the embryo. The stimulus for cystic change is unknown.
- The cyst presents most commonly in the fifth and sixth decades
- occurs more frequently in males than in females
- It may be asymptomatic and be discovered on routine radiographic examination, or present as a slowly enlarging swelling in the anterior region of the midline of the palate.
- Occasionally, it discharges into the mouth when the patient may complain of a salty taste.
- Pain may occur if the cyst becomes secondarily inflamed.
- Although cysts may arise at any point along the nasopalatine canal, most originate in the lower part and some arise entirely within the soft tissue of the incisive papilla. Such lesions are often designated cysts of the papilla palatina (Fig.).
nasopalatine duct cysts present as well-defined round, ovoid, or heart-shaped radiolucencies, often with a sclerotic rim (Fig.). They are usually symmetrical about the midline but some are displaced to one side. The cyst must be distinguished from the normal incisive fossa and although precise limits cannot be placed on the maximum size of the latter, it is generally accepted that a radiolucency not greater than 6 mm wide may be considered within normal limits. Where there are standing teeth, the lesion must also be differentiated from a radicular cyst.
The cysts may be lined by a variety of different types of epithelium. Stratified squamous epithelium, pseudostratified ciliated columnar (respiratory) epithelium often containing mucous cells, cuboidal epithelium, or columnar epithelium may be seen alone or in any combination (Fig.). The epithelium is supported by a connective tissue capsule which usually includes prominent neurovascular bundles from the terminal branches of the long sphenopalatine nerve and vessels. Collections of mucous glands and a scattered chronic inflammatory cell infiltrate are frequently present.