a 40-year - old male patient came with the complaint of pain and swelling in the anterior vestibular region for the past 2 weeks . history revealed recurrent episodes of pain and swelling and spontaneous remission following nasal discharge . on examination , the patient had a well - defined , fluctuant swelling obliterating the labial vestibule from 12 to 22 . the swelling also extended in the midpalatal region between two central incisors posteriorly up to the premolar level [ figure 1 ] . the central incisor exhibited mild grade 1 mobility buccopalatally without any movement in the corono - apical region . patient had poor oral hygiene and inflamed gingiva with 5 mm of gingival pocket in both central incisors . the periapical radiograph showed large triangular - shaped radiolucent lesion measuring about 2 cm diameter was present between the two maxillary central incisors [ figure 3 ] . the lesion had a thin radio - opaque margin with displacement of both the roots in a distal direction [ figure 4 ] . mild root resorption was observed in 21 root and the lesions also involved the periapical region of the two lateral incisors . the central incisors had bone only on the cervical region , and the remaining portion was completely in the radiolucent lesion . occlusal view radiograph revealed an oval radiolucent lesion from the central incisor to the 2 premolar region in the midpalatal region measuring about 3 cm  2 cm lesion . due to the proximity of the lesion to the nasal floor , cone - beam computed tomography ( cbct ) scan was taken to plan for the surgical procedure which clearly showed the complete breach of both the nasal floor and hard palate with hollowing in the anterior maxillary region [ figure 5 ] . based on the clinical and radiographic findings , provisional diagnosis of nasopalatine duct cyst was made . preoperative intraoral swelling preoperative ( a ) intraoral periapical radiograph , ( b ) occlusal radiographs orthopantamograph showing distal displacement roots of upper central incisors ( a and b ) cone beam computed tomography images of the lesion showing complete anterior palatine bone loss the patient was advised about the nature and severity of the lesion , and the complete bone loss of anterior palatine bone was explained . the significance of surgical enucleation of the lesion was explained to the patient and also advised for bone graft placement . the patient gave consent for the cyst enucleation but was not willing for bone grafting procedure . before the surgery , root canal treatment of the involved teeth was done , and complete scaling was done to improve the oral hygiene . before surgery , all preliminary investigations were done , and the results were within normal limit . due to the mild mobility of the central incisors , splinting of the teeth with arch bar the possibility of tooth avulsion or extractions of incisors were explained to the patient , and informed consent was obtained . as the cystic wall was found attached to the nasal mucosa and palatal mucosa , both labial and palatal approach were used [ figure 6 ] . the cyst was carefully dissected and enucleated , without breaching the nasal mucous membrane or the palatal mucosa . intraoperatively , the cyst was found to be a capsuled lesion which was adherent in the nasopalatine region of palatal mucosa but was not attached to the root or periodontal ligament . the flap was closed , and palatal acrylic plate was placed to support the palatal mucosa . histopathologically , it was found to have fibrous capsule with stratified squamous epithelial lining , and final diagnosis of nasopalatine duct cyst was confirmed [ figure 7 ] . intraoperative picture showing attachment of the cystic wall with ( a ) nasal mucosa , ( b ) palatal mucosa histopathological picture showing stratified squamous epithelium ( h and e , original magnification , 10 ) nasopalatine duct canal develops as a right and left side canal but generally fuses into single canal . however , three anatomical variations have been reported ; wherein , it sometimes appears as two parallel canals or single canal or a y - shaped canal . depending on the anatomical structure , the nasopalatine cyst appears as a midline cyst or paramedian cyst when it involves one side of the canal only . however , midline nasopalatine duct cyst is more common than the other types ( stafne 1969 ) . it has been postulated that localized trauma such as previous endodontic treatment , implant placement or infection or mucous retention may initiate the cellular proliferation and may give rise to nasopalatine duct cyst . it is not been associated with any habits such as smoking or alcoholism . in our study the cyst arises from the epithelial lining of nasopalatine duct or from the vomer nasal organ of jacobson or mucous glands present in the nasal mucosa . the epithelium close to the nasal floor has ciliated columnar epithelium , and the one closer to the oral cavity has squamous epithelium and the one in the middle has cuboidal epithelium . hence , the nasopalatine cyst also exhibits the mixed nature of the epithelial lining . in our case , it appears as either asymptomatic which is recognized on routine imaging or may present with pain or swelling or with other symptoms such as burning sensation , tooth displacement , nasal obstruction , or discharge into the nasal cavity or oral cavity . the size of the swelling is variable in size but most often it is < 2 cm in diameter . however , occasional cases of large and aggressive lesion up to 52 mm have been reported with complete destruction of labial and palatal bony plates . when the nasopalatine duct cyst present at higher level , there is not much effect over the tooth . the nasopalatine duct cyst when it is present at lower level always displaces the tooth and often considered characteristic of the lesion . however , it has been reported in association with nonvital tooth and periodontally compromised tooth . in our case , both the incisors were nonvital , and the patient had chronic periodontitis with poor oral hygiene . root resorption is uncommon ; however , shear and speight have reported cases with root resorption . radiographically , it appears as a round , ovoid , pear - shaped , or heart - shaped radiolucent lesion in the middle of the palate . bone expansion is uncommon , and usually , it causes resorption of bone . in our case , the cyst completely eroded the palatal bone and the nasal floor , and the swelling was fluctuant in nature . the average size of the normal nasopalatine fossa is 3 mm in anteroposterior , transverse , and in vertical direction . however , shear and speight have reported that the mean size of the nasopalatine fossa was as high as 10.19 + 3.24 mm anteroposteriorly and 4.79 + 1.33 mm in width . it is advised that if the radiographic size of nasopalatine fossa was < 10 mm without any signs and symptoms , it should be re - radiographed periodically . however , bodin , isaacson , and julin advised for surgical exploration if the size of the radiolucency exceeds 8 mm , or if it shows asymmetric bulging . aspiration of the radiolucent lesion will help to differentiate a normal nasopalatine fossa from the cyst . cbct is useful when planning for the surgical enucleation of the lesion as it clearly shows the proximity of the lesion with the nasal floor and the posterior extent in the hard palate . the differential diagnosis of the lesions includes odontogenic cysts and tumors such as dentigerous cyst , lateral periodontal cyst , cystic ameloblastoma , keratocystic odontogenic tumors , and periapical granuloma . however , marsupialization is considered in large lesions followed by second stage enucleation can be done . recurrence is uncommon following enucleation ; however , recurrence rate of 1130% has been reported in the literature . in our study , we used both palatal and vestibular approach as the cyst was large in size extending from nasal floor to palatal mucosa . paresthesia of the anterior palatal region has been reported in occasional cases following the surgery . apart from odontogenic cysts such as radicular cyst , dentigerous cyst , and odontogenic keratocyst , the nonodontogenic origin of cyst such as nasopalatine duct cyst also should be considered in the differential diagnosis of the radiolucent lesions in the anterior maxillary region . as per the literature review , nasopalatine duct cyst is considered a rare pathology , simple enucleation surgery is often considered curative .