A case of developing odontoma of the mandible with suspected BRAF p.V600E mutation

Abstract

Ameloblastic fibro-odontoma (AFO) is a rare benign mixed odontogenic tumor composed of proliferating odontogenic epithelium in a cellular ectomesenchyme with the formation of dental hard tissues, including enamel and dentin. According to the 2017 WHO Classification of Head and Neck Tumours, AFO is no longer defined as an independent entity but as part of a series of histological changes observed in a developing odontoma (DOD). Nevertheless, it is believed that this classification does not apply to all lesions diagnosed as AFO before 2017, some of which have neoplastic characteristics with BRAF p.V600E mutation. We report a case of DOD in the posterior mandible of an 8-year-old girl. Surgical excision was performed under general anesthesia. This case was diagnosed based on detailed clinical, radiological, and histopathological analyses. In addition, the mutant BRAF p.V600E was suspected by immunohistochemical analysis. BRAF mutation detection may contribute to accurately diagnosing the true neoplastic nature in odontomas. In the present case, no recurrence was observed until at least 11 months after surgery.