An Anterior Maxillary Radiolucency : Differential Diagnosis
Differential diagnosis
Periapical ( radicular ) cyst
Periapical ( radicular ) cysts are inflammatory odontogenic cysts , and the most common cyst of the jaws . 8 , 9 Radicular cysts arise from a preexisting periapical granuloma , which forms in response to necrotic tissue . 1 , 10 The resulting inflammation gives rise to the stimulation of epithelial cells from the rests of Malassez . 1 , 4 , 9 , 10 The increase in number of epithelial cells leads to radicular cyst formation at the apex of a non-vital tooth . 1 , 8 , 9 The apex or periapex of the tooth are the only locations of a periapical cyst ( Figure 2 ). Though these cysts can be seen clinically throughout any age of life , these cysts are usually found in patients in their third through sixth decades of life . 1 , 9 Generally , these lesions are asymptomatic , and are incidental findings on routine radiographic examination . With acute inflammatory exacerbation , signs and symptoms may include : swelling , pain , pus , and tooth mobility . 1 , 9 ,
10
Radiographically , these lesions are well-defined , unilocular radiolucencies with complete or partial thin cortication , which are usually less than 1.0 cm in diameter , but may expand if left untreated . 8 , 11 Treatment options for periapical cysts include : endodontic therapy , endodontic retreatment , or apicoectomy , but if the lesion persists usually the more aggressive approach of
11 , 12 enucleation and extraction is preferred .
Nasopalatine duct cyst ( NPDC )
Nasopalatine duct cysts are also known as incisive canal cysts . 13 While NPDCs may be present at any age of life , the greatest prevalence is from the fourth through sixth decades of life , with a slight male predilection . 13 The nasopalatine ducts usually undergo progressive degradation . The epithelial remnants proliferate and provide the source material for the NPDC . 1 , 14 The actual stimuli for cyst formation are uncertain ; however , bacterial infections / trauma are believed to play a role . 1 , 4 , 14 One distinguishing feature for this type of lesion is the presence of vital teeth adjacent to the lesion . 15 Radiographically , these lesions appear as well defined , wellcircumscribed radiolucencies , which are either round , oval , or heart shaped . 4 , 16 The upside down heart shape seen in Figure 3 is due to the shadow of the nasal spine superimposed on the cyst . Surgical enucleation , with biopsy , is the recommended treatment . Biopsy is recommended as a radiograph is not clinically diagnostic , and there are many lesions that are able to mimic a NPDC . 4
Keratocystic odontogenic tumor / Odontogenic keratocyst ( KCOT / OKC )
KCOT / OKCs are benign uni- or multicystic , intraosseous tumors that demonstrate aggressive and infiltrative behavior . The WHO reclassified these tumors from odontogenic keratocyst ( OKC ) to KCOT / OKC to reflect the neoplastic nature of the tumor in 2005 but re-classified them as cysts in 2017 . 17 The most accepted reasoning for the development of KCOT / OKC is that they arise from remnants of the dental lamina in the mandible and maxilla , 1 but more recent evidence suggests there may also be a genetic component with PTCH gene mutations . 1 , 17-20 KCOT / OKCs are a common clinical feature in Naevoid basal cell carcinoma syndrome ( NBCCS ) also known as Gorlin-Goltz syndrome . In fact , KCOT / OKCs are one of the most common features of NBCCS , occurring in 65-75 percent of all patients . 19 KCOT / OKCs can present at any age , but a peak incidence is seen in the second to third decades of life with males having a slight predilection . 17 KCOT / OKCs may be asymptomatic , especially when they are small in size . Larger KCOT / OKCs may present with pain , swelling , and discharge . 4 , 17 , 19 The most common location is the posterior body and ramus of the mandible . 4 , 19 Radiographically , a KCOT / OKC may appear as a well-defined radiolucency with corticated margins . 4 Larger KCOT / OKCs tend to be multilocular whereas smaller lesions tend to be unilocular as seen in Figure 4 . 1 Treatments for KCOT / OKCs can be difficult because different treatment modalities lead to highly variable recurrence rates ( 2-62 percent ). 18 The standard treatment involves enucleation and curettage ; however other methods such as peripheral ostectomy and cauterization using Carnoy ’ s solution or marsupialization have also been used to minimize recurrence or surgical morbidity , respectively . 4 , 18
CONCLUSION
Radiolucencies of the anterior maxilla may have overlapping radiographic features . We herein present a case of an intraosseous traumatic neuroma . However , the radiographic differential diagnosis for this lesion included a periapical cyst , nasopalatine duct cyst , and even a keratocystic odontogenic tumor / odontogenic keratocyst . Thus , this case illustrates the uncommon diagnostic possibilities that may be encountered in incidental periapical radiolucencies .
22 JANUARY / FEBRUARY 2018 | PENNSYLVANIA DENTAL JOURNAL