ODONTOGENIC MYXOMA: A CASE REPORT AND LITERATURE REVIEW

Abstract

<h3>Background</h3> Odontogenic myxoma (OM) is a rare intraosseous neoplasm that is benign but locally aggressive. It is derived from the mesenchymal portion of the tooth germ. Even though it is a benign lesion, it can cause considerable morbidity because of its invasive nature. Therefore, it is important to delineate the margins of OM to achieve a better treatment outcome. We present the case of a mandibular odontogenic myxoma in a 72-year-old male patient, whose chief complaint was swelling and pain on the lower left side of the face. The patient underwent imaging at Tokyo Medical and Dental Hospital for further evaluation. <h3>Objective</h3> The aim of this report is to present a case of odontogenic myxoma in an older patient, with computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of OM and a literature review. <h3>Materials and Methods</h3> CT was performed with a 64-row multidetector CT (MDCT) scanner (Somatom Sensation 64, Siemens Healthcare, Erlangen, Germany) and magnetic resonance imaging (MRI) was performed with a 3 T MRI unit (Magnetom Spectra, Siemens Healthcare, Erlangen, Germany) with a 16-channel head and neck coil. <h3>Results</h3> The initial panoramic study showed a poorly defined lytic lesion in the left ramus in close proximity to the inferior alveolar canal. CT revealed a hypodense lesion with a thinned out buccal cortex and a disrupted lingual cortex. Axial T1-weighted MRI showed a well-demarcated, low-intensity lesion in the posterior left mandible. An axial T2-weighted sequence displayed a well-defined, hyperintense mass. In a fat-suppressed T2 scheme, the lesion was even more conspicuous. The mass further displayed a high mean apparent diffusion coefficient value of 1.74 × 10^-3 mm²/s. Aneurysmal bone cyst, central hemangioma, odontogenic myxoma, and central giant cell granuloma were considered as differential diagnoses. After histopathologic evaluation, a definitive diagnosis of odontogenic myxoma of the left mandible was made. The lesion was treated with segmental mandibulectomy. The distribution of odontogenic myxoma by age, gender, and imaging modality was studied retrospectively in the literature review. patient age range was 0 to 80 years, and there was a male predilection. Mean ages of female and male patients were 40.5 years and 56.75 years, respectively. The distribution of imaging modalities was 40% for conventional methods, 45% for CBCT/CT and 15% for MRI. <h3>Discussion</h3> In the present study, MRI features, such as the hyperintense signal on T2-weighted images and low-signal intensity on T1-weighted images, were consistent with those of cases reported in the literature. Although CT could delineate the lesion and its extent, MRI was more effective in accurately delineating margins and determining the extent of the tumor for better guidance of the surgical procedure. MRI should, therefore, be considered the imaging modality of choice for diagnosis and margin delineation of OM because this tumor demonstrates a high recurrence rate. All 3 imaging modalities have inherent advantages and disadvantages; however, all of these modalities should be routinely used in the diagnosis of OM. Results of MRI can further help map the margins and greatly aid in resection with clear margins.