2.2 Investigation and Differential Diagnosis
Orthopantomography (OPG) and cone beam computed tomography (CBCT) was promptly ordered. They depicted a well-defined, multiloculated expansile osteolytic lesion with few small septa spreading inside the lesion. Expansion of the buccal cortex with areas of cortical destruction and root resorption of mandibular left central incisor, right central and lateral incisors were also noticed. The lesion measured 31.2 x 21.0 mm extending from the left mandibular first premolar to the right mandibular canine (Figures 2, 3). Radiographic preliminary differential diagnosis included central giant-cell granuloma (CGCG), odontogenic keratocyst (OKC), ameloblastoma, odontogenic myxoma, and fibroameloblastoma.
An incisional biopsy was then conducted and the histopathological specimen showed an irregular piece of soft tan-pink tissue with fragile consistency. Cut sections demonstrated homogenous myxoid pink surface containing hemorrhagic foci. The microscopic analysis revealed striated muscle fibers, some reactive new and pre-existing bone trabecula and presence of a neo-formed tissue composed of haphazardly arranged stellate and spindle cells with no atypia in an abundant loose myxoid stroma containing few collagen fibrils which was consistent with histopathological features of odontogenic myxoma and therefore a definitive diagnosis was made (Figure 4).