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 Table of Contents  
CASE REPORT
Year : 2014  |  Volume : 26  |  Issue : 3  |  Page : 338-341

Role of cone beam computed tomography in the prompt diagnosis of a nasopalatine duct cyst


1 Department of Oral Medicine and Radiology, Institute of Dental Studies and Technologies, Modinagar, Uttar Pradesh, India
2 Private Practice, Gurgaon, Haryana, India

Date of Submission27-Aug-2014
Date of Acceptance09-Nov-2014
Date of Web Publication19-Nov-2014

Correspondence Address:
Sapna Panjwani
Department of Oral Medicine and Radiology, Institute of Dental Studies and Technologies, Kadrabad, Modinagar, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-1363.145023

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   Abstract 

The nasopalatine duct cyst (NPDC) is the most common of all the developmental, epithelial, and non-odontogenic cysts of the maxilla, believed to originate from the epithelial remnants of the nasopalatine duct. Typically, the lesion is asymptomatic and is detected accidentally on a radiograph. The definite diagnosis must be based on the clinical, radiological, and histopathological findings. Frequently misdiagnosed, the NPDC is not rare. The motive of reporting an entity that is not very rare is that the lesion is mostly misdiagnosed, and to emphasize the importance of cone-beam computed tomography (CBCT) in the diagnosis and optimized treatment planning of NPDCs.

Keywords: Cone-beam computed tomography, diagnosis, nasopalatine duct cyst, radiograph, radiolucency


How to cite this article:
Panjwani S, Arora S, Rai S, Malik R. Role of cone beam computed tomography in the prompt diagnosis of a nasopalatine duct cyst . J Indian Acad Oral Med Radiol 2014;26:338-41

How to cite this URL:
Panjwani S, Arora S, Rai S, Malik R. Role of cone beam computed tomography in the prompt diagnosis of a nasopalatine duct cyst . J Indian Acad Oral Med Radiol [serial online] 2014 [cited 2022 May 22];26:338-41. Available from: https://www.jiaomr.in/text.asp?2014/26/3/338/145023


   Introduction Top


Although conventional radiography plays a pivotal role in the diagnosis of dental disease, it is a two-dimensional (2D) representation of three-dimensional (3D) objects, with significant structure superimposition and unpredictable magnification. [1] The advent of medical computed tomography, in 1972, revolutionized the field of medical imaging, but the major concern was the large radiation dose, cost, and large size of the machine. With the increasing use of computed tomography (CT) scans for the standard treatment plans of diseases in the orofacial region, a less expensive, lower dose method of obtaining radiographic 3D volume data was required. Recognizing this need, the first cone-beam computed tomography (CBCT) scanner was developed in 1997. [1] Cone-beam computed tomography allows true 3D visualization of the dentoalveolar structures, overcoming the major precincts of conventional radiography.[1]

Non-endodontic lesions are often misdiagnosed as pathoses of endodontic origin. One of the non-odontogenic cysts of the oral cavity, the nasopalatine duct cyst (NPDC), can often be misdiagnosed as being endodontic in nature. [2] The nasopalatine duct cyst is the most common of all the developmental, epithelial, and non-odontogenic cysts of the maxilla, believed to originate from the epithelial remnants of the nasopalatine duct. [3] The etiology of NPDC is unknown, but the possible causes include trauma, infection, and spontaneous proliferation. [4]

Most of the patients are unaware of any marked clinical symptoms and the cyst is usually detected accidentally during routine radiographic examination. Complaints usually include swelling, drainage, and pain, which are often found in association with an infection of a previously asymptomatic cyst. [5]

On account of the notching by the nasal septum during the expansion of the cyst or because of the superimposition of the nasal spine on the radiolucent area, radiographically, the lesions may appear heart-shaped. [6] The NPDC occurs in the incisive canal and it may be difficult to differentiate it from a large incisive foramen. Variations in the dimensions of radiolucency have been reported by several authors. According to Shear and Speight, radiolucency with anteroposterior dimensions of up to 10 mm, in the incisive fossa region, may be normal. On the contrary, Bodin et al. proposed that exploratory surgery must be an option when there is a pronounced radiolucency with a thin cortical border on the periphery exceeding 8 mm in width, particularly if the lesion is asymmetrically bulging. They also proposed that radiolucencies exceeding 14 mm in diameter were always cysts. [7] The 2D representation of the 3D anatomy of the cyst on a conventional radiograph gives rise to this ambiguity. The CBCT and its potential for 3D CT-based surgical planning and measurement helps in the evaluation of the nasopalatine canal and erasing this ambiguity. [7]


   Case Report Top


A 14-year-old male patient reported with a chief complaint of salty discharge from the upper front region of the jaws since seven to eight months. The patient experienced the discharge twice or thrice in a month, which was preceded by swelling in the upper front region (behind the teeth). There was no history of trauma. Careful intraoral examination did not reveal any significant findings. On the basis of the history and clinical examination, a provisional diagnosis of dentoalveloar abscess in relation to 11 and 21 was made, not taking the negative history of trauma into account. Following this, the patient was subjected to a radiographic examination. An intraoral periapical radiograph (IOPA) [Figure 1]a, maxillary cross-sectional occlusal radiograph [Figure 1]b, and orthopantomography (OPG) were done. These radiographs revealed the presence of a well-defined, ovoid-shaped radiolucency with approximate dimensions of 6 × 4 mm, in between the roots of 11 and 21, in the region of the incisive foramen. The radiolucency was associated with displacement of the roots of 11 and 21. Although the divergence of the roots was evident in the conventional radiographs, the exact dimensions could not be gauged and also due to anatomical overlapping, the exact boundaries of the lesion and possible involvement of the nasal cavities were not totally clear. On checking the pulp vitality, the associated teeth were found to be vital. On the basis of the radiographic features, the working diagnosis of a nasopalatine duct cyst was made.

For an elaborative assessment of the lesion, the patient was subjected to CBCT, with a small field of view (FOV) of the anterior maxilla. The CBCT examinations were made using a Kodak 9000 3D digital imaging system (Carestream Dental LLC, Atlanta, GA, USA). The scan revealed dilatation of the nasopalatine foramen with a large, well-defined, corticated, and oval-shaped radiolucency, with maximum transverse dimensions of 6.4 × 5.3 mm (measured from the inner cortex). Periodontal space widening in relation to 21 and divergence of the roots of 11 and 21 were also evident. The axial slice also revealed the presence of perforation along the palatal aspect of the lesion, which was not otherwise evident in the plain radiographs [Figure 2], [Figure 3], [Figure 4].
Figure 1: (a) IOPA radiograph of 11 and 21, and (b) a maxillary crosssectional occlusal radiograph, showing a well-defined and ovoid-shaped radiolucency between the roots of 11 and 21, with displacement of the roots

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Figure 2: A 3D reconstructed image of the cyst

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Figure 3: Axial slice of the maxilla demonstrating maximum transverse dimensions of the cyst

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Figure 4: Sagittal sections of the area of interest demonstrating perforation along the palatal aspect and bucco-lingual dimensions

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Endodontic treatment of the incisors was done [Figure 5] and an obturator was fabricated to be used postoperatively for better patient compliance, facilitating postoperative healing and preventing hematoma formation [Figure 6]. Surgical enucleation of the cystic lining along with apicoectomy of the incisors, with retrograde filling, was performed, and the specimen [Figure 7]a was sent for histopathological examination. The diagnosis of nasopalatine duct cyst was confirmed histopathologically [Figure 7]b. The postoperative course was uncomplicated and there was no recurrence in the one year follow-up.
Figure 5: IOPA radiograph of 11 and 21 showing obturated canals in 11 and 21

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Figure 6: Obturator fabricated to be used postoperatively for better patient compliance facilitating postoperative healing and preventing hematoma formation

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Figure 7: (a) Excised tissue specimen and (b) a histopathological picture (10×)

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   Discussion Top


The nasopalatine duct cyst, called the incisive canal cyst, also described in literature as a cystis canalis nasopalatini and cystis canalis incisive, is the most common non-odontogenic cyst occurring in the oral cavity. [8] In the past, it was considered as a fissural cyst; however, according to the World Health Organization (WHO) classification, it is now considered to be a non-odontogenic, developmental, epithelial cyst of the maxilla. In most of the cases, it develops in the midline of the palate near the incisive foramen. [9]

In imaging examination, NPDC presents as a radiolucency, with a well-defined oval or circular area circumscribed by a radiopaque halo, close to or on the midline of the anterior maxillary region, between the apices of the upper central incisive teeth. This radiolucent area may show a 'heart' shape because of the image of the anterior nasal spine overlapping it. [10] On account of the variable size of the incisive canal and foramen, differentiating a large incisive foramen and a small asymptomatic incisive canal cyst on the basis of radiographic evidence alone is difficult. In the absence of other symptoms, radiolucencies of the incisive canal less than 0.6 cm in diameter must not be considered cystic. Advanced imaging methods like computed tomography and magnetic resonance imaging (MRI) can be used to differentiate this entity from other lesions, although a definitive diagnosis can be made easily on plain films. [11]

The introduction of CBCT epitomized an important new development in dentomaxillofacial radiology and precipitated a shift from two- to three-dimensional data acquisition, image reconstruction, and visualization. [11] Cone-beam computed tomography enables analysis of the dimension of the cyst, analysis of the involvement of neighboring anatomical structures, and assists in treatment planning. [11] Cone-beam computed tomography enables image reconstruction, assesses different angles, accurately identifies the pathology and their extension into the adjacent tissues, as well as suggests intralesional content based on the linear lesion attenuation coefficient. [12]

An enlarged nasopalatine duct (less than 6 mm in diameter), a central giant cell granuloma, a radicular cyst associated with the upper central incisors, a follicular cyst associated with mesiodens, primordial cyst, nasoalveolar cyst, osteitis with palatal fistulization, and bucconasal and/or buccosinusal communication could be considered under the list of differential diagnoses. [13] The present case had classical radiographic and histopathological features of an NPDC. Following resection, relapse is unlikely, although a postoperative follow-up of at least one year is indicated in all cases.

Conventional radiography might not produce sufficient information about the upper extension of the lesion. Cone-beam computed tomography can provide high-resolution images, with a short scanning time, at a reduced radiation dose. Cone-beam computed tomography, therefore, provides the opportunity for multiplanar imaging and 3D information. Cone-beam computed tomography in our case has depicted a perforation along the palatal aspect of the lesion, which was not otherwise evident in the plain radiographs. An increased understanding of the anatomy, the use of appropriate diagnostic tests to include CBCT imaging, and key examination techniques to distinguish endodontic lesions from non-endodontic pathoses are imperative for an accurate differential diagnosis and appropriate treatment outcome. Cone-beam computed tomography easily visualizes the radio transparency in the midline, with well-defined sclerotic margins, and demonstrates the exact location of the lesion. In addition, it facilitates planning for the best surgical approach.


   Conclusion Top


The nasopalatine duct cyst is the most common of all the developmental, epithelial, and non-odontogenic cysts of the maxilla, believed to originate from the epithelial remnants of the nasopalatine duct. The definite diagnosis should be based on clinical, radiological, and histopathological findings. The motive of reporting an entity that is not very rare is that the lesion is mostly misdiagnosed, and also to emphasize the importance of CBCT in the diagnosis and optimized treatment planning of NPDCs.

 
   References Top

1.Tetradis S, Anstey P, Graff-Radford S. Cone beam computed tomography in the diagnosis of dental disease. J Calif Dent Assoc 2010;38:27-32.  Back to cited text no. 1
    
2.Hilfer PB, Bergeron BE, Ozgul ES, Wong DK. Misdiagnosis of a nasopalatine duct cyst: A case report. J Endod 2013;39:1185-8.  Back to cited text no. 2
    
3.Fating C, Gupta R, Lanjewar M, Nayak B, Bakshi A, Diwan R. Nasopalatineduct cyst: A rare case report. Chhattisgarh Journal of Health Sciences 2013;1:103-6.  Back to cited text no. 3
    
4.Ely N, Sheehy EC, McDonald F. Nasopalatine duct cyst: A case report. Int J Pediatr Dent 2001;11:135-7.  Back to cited text no. 4
    
5.Dedhia P, Dedhia S, Dhokar A, Desai A. Nasopalatine duct cyst. Case Rep Dent 2013;2013:869516.  Back to cited text no. 5
    
6.Cicciù M, Grossi GB, Borgonovo A, Santoro G, Pallotti F, Maiorana C. Rare bilateral nasopalatine duct cysts: A case report. Open Dent J 2010;4:8-12.  Back to cited text no. 6
    
7.Thakur AR, Burde K, Guttal K, Naikmasur VG. Anatomy and morphology of the nasopalatine canal using cone-beam computed tomography. Imaging Sci Dent 2013;43:273-81.  Back to cited text no. 7
    
8.Szubert P, Sokalski J, Krauze A, Kondziela I, Sp³awa-Neyman A. Nasopalatine duct cyst- Case reports. Dent Med Probl 2010;47: 508-12.  Back to cited text no. 8
    
9.Escoda Francolí J, Almendros Marqués N, Berini Aytés L, Gay Escoda C. Nasopalatine duct cyst: Report of 22 cases and review of the literature. Med Oral Patol Oral Cir Bucal 2008;13:E438-43.  Back to cited text no. 9
    
10.Malaquias PT, Costa MV, Ribeiro IL, Batista AS, Sarmento VA, Bomfim RT. Computed tomography for diagnosis and therapeutic planning of nasopalatine duct cyst clinical case report. Arch Health Invest 2013;2:3-7.  Back to cited text no. 10
    
11.Basso EC, Neto ER, Dib LL, Costa C. An unusual case of nasopalatine cyst in Brazilian population. J Health Sci Inst 2012;30:292-4.  Back to cited text no. 11
    
12.Suter VG, Sendi P, Reichart PA, Bornstein MM. The nasopalatine duct cyst: An analysis of the relation between clinical symptoms, cyst dimensions, and involvement of neighboring anatomical structures using cone beam computed tomography. J Oral Maxillofac Surg 2011;69:2595-603.  Back to cited text no. 12
    
13.Kalwa P, Sholapurkar AA, Joshi V. Surgical management of nasopalatine duct cyst: Case report. Rev Clín Pesq Odontol 2010;6:81-6.  Back to cited text no. 13
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]


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[Pubmed] | [DOI]



 

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