Rapidly Expanding Odontogenic Myxoma: An Entity With Diagnostic Challenges—A Case Report

Odontogenic myxoma is a rare benign odontogenic tumor having locally aggressive behavior. It frequently affects the females in the second or third decade of life and commonly occurs in the mandibular posterior region as a slow-growing lesion. The aggressive behavior is often seen in maxillary lesions. However, this case report describes odontogenic myxoma with aggressive or rapidly expanding behavior occupying the ramus and angle of the mandible in few months. An 18-year-old girl reported with a chief complaint of gradually increasing painless swelling in the posterior region of the mandible for 4 months. Extraoral examination revealed diffuse, firm to hard, nontender swelling on the left mandibular posterior region and intraorally missing mandibular left third molar with expansion in the buccal and lingual aspect in the mandibular posterior region. Radiographic features depicted large well-defined multilocular radiolucency and impacted mandibular left third molar. Based on clinical features and radiographic findings, ameloblastic fibroma, dentigerous cyst, unicystic ameloblastoma, and odontogenic keratocyst were the entities considered in differential diagnosis. However, the histopathological examination confirmed it as odontogenic myxoma which was then treated surgically. This concludes that though radiographic examination is the first step meant for diagnosis, odontogenic myxoma depicts variety of radiographic features mandating histopathological examination for confirmation of the diagnosis.