|Year : 2016 | Volume
| Issue : 1 | Page : 18-21
Sunburst appearance in odontogenic myxoma of mandible: A radiological diagnostic challenge
Sahil Mustafa Kidwai1, Ravi Prakash Sasankoti Mohan1, Vijay Wadhwan2, Nagaraju Kamarthi1, Sumit Goel1, Swati Gupta1
1 Department of Oral Medicine and Radiology, Subharti Dental College and Hospital, Meerut, Uttar Pradesh, India
2 Department of Oral Pathology, Subharti Dental College and Hospital, Meerut, Uttar Pradesh, India
|Date of Web Publication||19-Feb-2016|
Ravi Prakash Sasankoti Mohan
Department of Oral Medicine and Radiology, Subharti Dental College and Hospital, Meerut, Uttar Prades
Source of Support: None, Conflict of Interest: None
Odontogenic myxoma in the jaws is infrequent, accounting for only 3%-6% of odontogenic tumours. The radiological appearance of this tumor is complicated and there exist controversies regarding its internal structure and locularity. The "sunray" or "sunburst" appearance in Odontogenic myxoma has been reported in the literature although rarely. Here we report a case of odontogenic myxoma in the mandible showing sunburst appearance which posed a diagnostic dilemma for the oral radiologists. We also emphasize the usefulness of Cone Beam Computed Tomography in the diagnosis of such lesions.
Keywords: Cone beam computed tomography, mandible, odontogenic myxoma, sunburst appearance
|How to cite this article:|
Kidwai SM, Mohan RS, Wadhwan V, Kamarthi N, Goel S, Gupta S. Sunburst appearance in odontogenic myxoma of mandible: A radiological diagnostic challenge. J Oral Maxillofac Radiol 2016;4:18-21
|How to cite this URL:|
Kidwai SM, Mohan RS, Wadhwan V, Kamarthi N, Goel S, Gupta S. Sunburst appearance in odontogenic myxoma of mandible: A radiological diagnostic challenge. J Oral Maxillofac Radiol [serial online] 2016 [cited 2022 Jan 27];4:18-21. Available from: https://www.joomr.org/text.asp?2016/4/1/18/177065
| Introduction|| |
Myxomas of the head and neck are rare tumors. Odontogenic myxoma (OM) is a rare, nonencapsulated benign but locally invasive odontogenic tumor first described by Thoma and Goldman in 1947.  It represents 3%-6% of all odontogenic tumors. , The evidence for its odontogenic origin arises from its almost exclusive location in the tooth bearing areas of the jaws, its occasional association with missing or unerupted teeth, and the presence of odontogenic epithelium. ,,
Most of the reported cases of OM are in young adults usually in their second and third decade of life and these lesions have marked female predilection. Although intraosseous myxoma has been reported in various anatomical sites, the majority of these tumors occur in the mandible, followed by the maxilla. ,,,
In the facial region, OM occurs mostly within the bone and radiologic examination is therefore important. Generally, diagnosis of OM is made by the examination of conventional radiographs (CRs) and confirmed by histopathology. Advanced technologies such as computed tomography (CT), Cone Beam Computed Tomography (CBCT) and magnetic resonance imaging (MRI) may offer diagnostic options, which could overcome some of the limitations of CR. ,,
The radiological appearance of the OM is more complicated than has generally been thought.  Indeed, there is considerable debate and controversy regarding the internal structure and locularity of the tumor. Radiologically, the appearance may vary from a unilocular radiolucency to a multicystic lesion with well-defined or diffused margins with fine, bony trabeculae within its interior structure expressing a "honey combed," "soap bubble," or "tennis racket" appearance. ,, The "sunray" or "sunburst" appearance in OM has been reported in the literature although rare. Here we report a case of odontogenic myxoma showing sunray appearance which posed a diagnostic dilemma for the oral radiologists.
| Case Report|| |
A 28 year old male of Asian origin reported with pain in the right lower back tooth region since past 6 months. History revealed that he had undergone tooth extraction due to deep caries which was causing the pain in the same region six months back after which he developed a swelling in that region. He visited a local dentist for the same who performed an incisional biopsy in the right mandibular molar area. The biopsy report confirmed the swelling as peripheral fibroma. However, the pain did not subside and even the biopsy site remained unhealed for one month. Patient had no significant medical history. He was non smoker and non alcoholic. On extraoral examination there was no gross facial asymmetry and lymph nodes were non palpable. However, on palpation there was a bony hard swelling in the right lower border of mandible. Intraoral examination revealed a non indurated shallow ulcer on the alveolar ridge with a hard swelling of approx 3 cm × 3 cm in size due to both buccal and lingual cortical expansion [Figure 1]. The mucosa overlying the swelling was pale pink in color with few areas showing keratosis due to secondary trauma from opponent teeth. The area was mildly tender. On hard tissue examination, 37, 47 and 48 were missing. On the basis of history of extraction and clinical presentation of non healing ulcerative area and swelling, a provisional diagnosis of osteomylitis was made. On conventional panoramic examination, a mixed radiolucent and radiopaque lesion was seen with severe bony resorption in the right body of the mandible. Moreover there were radioapaque bony spicules emanating from the inferior aspect of the lesion giving a characteristic sun ray/sunburst appearance. Mandibular lateral occlusal projection revealed buccal and lingual cortical expansion and internal septas [Figure 2]. Cone beam computed tomography views demonstrated the exact extent of the lesion along with clear visualization of internal septas and periosteal reaction [Figure 3]. The 3D reconstruction further helped in visualizing the lesion in three dimensions [Figure 4]. The radiological differential diagnosis made was metastatic lesion, osteosarcoma, odontogenic myxoma, ossifying fibroma or central hemangioma. Consent form was filled by the patient and complete surgical excision was performed and the excised specimen was sent for histopathological examination. The gross excised specimen was gelatinous and slippery. Radiograph of the specimen clearly exhibited internal septae and bony spicules [Figure 5]. Histopathological examination revealed hyperplastic stratified squamous epithelium with stellate, spindle, round cells in loose myxoid stroma. Odontogenic epithelial rests and mixed inflammatory cells were also evident. Moreover, myxoid matrix stained positively with alcian blue [Figure 6]. Thus histopathology confirmed the final diagnosis of odontogenic myxoma. The patient is on regular follow up without any discomfort.
|Figure 1: A non indurated shallow ulcer on the alveolar ridge with mild cortical expansion|
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|Figure 2: Mandibular lateral occlusal projection showing buccal and lingual cortical expansion and internal septas|
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|Figure 3: Cone beam computed tomography views showing the extent of the lesion along with clear visualization of internal septas and sunburst appearance|
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|Figure 4: The 3D reconstruction visualizing the lesion in three dimensions showing clearly the bony spicules emanating from the inferior aspect of the lesion giving sunburst appearance|
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|Figure 6: Histopathological examination showing myxoid matrix staining positively with alcian blue and hyperplastic stratified squamous epithelium with stellate, spindle, round cells in loose myxoid stroma|
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| Discussion|| |
Odontogenic myxoma is a rare aggressive intraosseous lesion derived from embryonic mesenchymal tissue associated with odontogenesis primarily consists myxomatous ground substance with widely scattered undifferentiated spindled mesenchymal cells.  Clinically, odontogenic myxoma is a benign, painless, invasive, slowly enlarging mass. Large lesions can cause marked asymmetry of the face. It causes expansion of bony cortices, displacement and loosening of teeth. ,, In the present case, the lesion appeared as a bony hard swelling with expansion of bony cortices along with a non indurated shallow ulcer on the alveolar ridge. However, because there was history of extraction, swelling and presence of a non healing ulcer, we made osteomyelitis as our clinical diagnosis.
Zhang et al., classified radiographic appearances of OM into six types:
Type I: Unilocular well-defined radiolucency,
Type II (multilocular): Two or more compartments with multiple interlaced osseous trabeculae described as honey comb, soap bubble or tennis racquet radiolucency,
Type III: Lesion located in alveolar bone,
Type IV: Lesion involving the maxillary sinus,
Type V (moth eaten appearance): Larger radiolucent area with irregular borders,
Type VI: Combination of bone destruction and bone formation giving sun ray appearance. , Our case is thus classified as Type VI.
The sunburst pattern is a classic finding in bone sarcomas such as osteosarcoma and chondrosarcoma. On close examination, these spicules are not truly straight, but instead form irregular, slightly wavy lines.  In literature such mimicking pattern is also reported in some odontomas, odontogenic myomas, solitary plasmacytomas, metastasis (especially from sigmoid colon and rectum), mandibular squamous cell carcinoma, haemangioma, tubercular osteomylitis and fibrous dysplasia although rarely. , Therefore, in present case, we included osteosarcoma in our radiological differential diagnosis along with odontogenic myxoma.
On panoramic radiographs, expansion of the tumor can be assessed visually, taking into consideration the 2-dimensional (2-D) nature of the images and by degree of displacement of the associated teeth accompanied by distortion, thinning, and/or perforation of the cortex. ,, In some of the maxillary tumors the tumors growns silently inside the maxillary sinus, resulting in opacification, also reported by other investigators. , MRI has the ability to demonstrate the tumors vividly with precise determination of the margins. The walls of the tumors and patterns of the growth are clearly depicted in this imaging modality.  It is mainly useful in case of maxillary tumors. In the present case, Panoramic radiograph was not very useful in visualization of internal aspect of the lesion. MRI was not performed in our case as it is more useful in maxillary tumors.
Computed tomographic images of odontogenic myxomas may show any osteolytic expansile lesions with mild enhancement of the solid portion of the mass or bony expansion and thinning of cortical plates with strong enhancement of the mass lesion. Cone beam CT of a limited area is very effective in reducing the radiation dose in patients and achieving high spatial resolution in comparison with conventional CT. Moreover, it has wide applications and can be used to determine the extent and condition of the internal structure of lesions, fracture of teeth roots, the relationship between the apex of adjacent teeth and the mandibular canal, the condition of impacted teeth, diagnosis of temporomandibular joint disorders and the condition of alveolar bone when planning implant treatment.  An advantage of CT and CBCT is the ability for 3-D modeling which are valuable in assessing the true extent of the tumor, particularly with reference to planning reconstructive procedures as seen with the present case. 
The excised mass exhibits a whitish, translucent, mucinous appearance.  Histologically the WHO (1992) defined OM as "A locally invasive neoplasm consisting of rounded and angular cells lying in an abundant mucoid stroma". ,, They show loose myxoid stroma containing spindle-shaped, angular or round cells. Polymorphic cells or nuclei are rarely encountered. Stroma shows very few fine fibrillar material and minimum vascularity. Inflammatory infiltration and remnants of odontogenic epithelium are occasionally seen. ,, The ground substance of odontogenic myxomas has been shown to consist of about 80% hyaluronic acid and 20% chondroitin sulfate. The myxoid intercellular matrix stains positively with alcian blue as seen with the present case.  Immunohistochemical studies demonstrated positive reaction with antibodies to vimentin and actin, and negative reaction to antibody to S-100 protein. 
The aggressive nature of OM is well documented in the literature. The tumor is not radiosensitive, and the surgery is the treatment of choice. Radical treatment of en-block resection is advised by most authors over conservative treatment due to its invasive nature, large size, and recurrence history. ,, The prognosis is usually good. However recurrence ranging from 10%-33% is reported with conservative treatment. ,
| Conclusion|| |
In conclusion, the importance of radiology in the diagnosis of OM cannot be ruled out as this tumor occurs inside the bone and can reach a considerable size with little or no clinical manifestations. In addition, good imaging is essential in visualization of tumor's boundaries before surgical treatment. Conventional radiographs, CT, CBCT and MRI whenever indicated, are essential in the diagnosis of OM to see the extension of the tumors, status of cortication, expansion, locularity, and extension into the surrounding structures. However, definitive diagnosis can only be made through histopathological examination in addition to clinical and radiographic examinations. The present case adds to literature another rare case of odontogenic myxoma showing sunburst appearance.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]