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