Nasopalatine Duct cyst: A Clinical Deception

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Figure 2. Showing a swelling in the incisive papilla (Black arrow) and swelling around the nasopalatine canal (White arrow)

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2.1. Radiographic examination

Figure 3. Showing Heart Shaped radiolucency in the periapical region of 11 and 21

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Intraoral periapical radiograph of upper anterior teeth, Maxillary Cross sectional occlucal view and Digital Panoramic radiographrevealed a well-defined unilocular Heart Shaped radiolucency between the 2 maxillary central incisors, measuring roughly about 2.0 X 2.5 cms with sclerotic rim. The Lamina dura of 11 and 21 were visible except in the apical 3^rd of mesial root surface of 21. The lesion seemed to have caused slight divergence of the roots of both the upper central incisors. Intraoral periapical radiograph of upper anterior teeth showed no evidence of interdental bone loss. Radiological findings were consistent with Nasopalatine cyst. Root canal therapy was carried out for incompletely treated 11,12, & 21.

Figure 4. Maxillary cross sectional occlusal view showing well defined heart shaped radiolucency.

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Figure 5. Showing no change in size of the lesion 4 months following endodontic treatment

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Four months following the RCT of 11,21, & 22, a second IOPAR was taken, which showed no evidence of regression of swelling. Thus enucleation was of the cyst was done and sent for histopathological examination.

2.2. Histopathological Examination

Microscopic examination H&E stained section showed cystic lumen lined by pseudostratifiedcolumnar epithelium. Flask shaped goblet cells were seen dispersed within the epithelium. Underlying connective tissue was loose and edematous. No evidence of nerves, arteries and veins in the cystic wall.

Thus the clinicopathological findings were suggestive of Nasoplalatine Cyst.

Patient was monitored regularly for a period of 3 months but the patient failed to show for subsequent appointments.

Figure 6. Histopathology of the Specimen showing cystic lumen lined by pseudo stratified columnar epithelium

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3. Discussion

Nasopalatine duct cyst is the most common non-odontogeniccyst of the oral cavity occring in general population.The Nasopalatine duct can be divided into two types: cyst of the incisive canal and cyst of the incisive papilla, both showing the same pattern of growth ^[2].

The nasopalatine canal usually contains remnants of the nasopalatine duct, a primitive organ of smell, and the nasopalatine vessels and nerves. Occasionally a cyst forms in the nasopalatine canal when these embryonic epithelial remnants of the nasopalatine duct undergo proliferation and cystic degeneration.

These lesions are almost three times morefrequent in males than in females. ^[7] The gender was not in favour in our case although in a case series conducted by Escoda-Francolí J et al showed that NPDCs affected both males and females equally, with only a slight predominance among the former ^[4].

The majority of cases occur in the third to the sixth decade of life. ^[4] This was in agreement, as the age of the patient in our case was 30 years.

The aetiologyof this lesion is still uncertain, however NPDC are hypothesized to arise from spontaneous cystic degeneration of remnants of the nasopalatine duct and some genetic determinants have been suggested. ^[4] Although its etiology remains unknown, some agents are implicated as trigger factors especially trauma, infection and spontaneous proliferation. ^[1] A Case report of a pathologic process in the adjacent teeth with suspected dissemination to the nasopalatine duct have been reported in literature. ^[7] In our case, access opening was performed by a Private practitioner even before the patient reported to us but an Intraoral Periapical radiograph of maxillary central incisors showed that the lamina dura in apical 3^rd of mesial root surface of 21 was not clearly visible. Thus a Periapical lesion was suspected which could have triggered the NPDC formation.

Testing the pulp vitality of the involved teeth and lamina dura analysis are very important aids in having correct diagnosis, especially to differentiate odontogenicperiapical lesions from NPCD, as in the nasopalatine duct cyst the lamina dura will be intact. ^[1] Pulp vitality was not performed in our case as access opening and pulp extirpation of 11, 21 was already performed by a Private dental practitioner even before the patient reported to us.

NPDC are usually slow growing, asymptomatic, with the lesion being detected on routine radiographs; however, many will present with one or more symptoms as in our case where the patient presented with pain. This could be attributed to an infection from a previously asymptomatic nasopalatine duct cyst or pressure of nasopalatinenerve. Also in our case the clinical working diagnosis of nasopalatine duct cyst was strongly established after a radiographic examination.

NPDC can be superficial or deep based on the Location of the cyst. Superficial swelling is usually fluctuant and blue if the cyst is near the surface. The deeper nasopalatine duct cyst is covered by normalappearing mucosa unless it is ulcerated from masticatory trauma ^[4].

Figure 7. Showing two most frequent locations of NPDC [4]

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