Ameloblastic Fibroma: A Rare Entity of the Mandible

Abstract

Abstract Ameloblastic fibroma (AF) is an uncommon benign odontogenic true mixed tumor comprising neoplastic epithelial and mesenchymal tissues. It constitutes only approximately 2% of odontogenic tumors and is defined by the World Health Organization (WHO) as “neoplasm composed of proliferating odontogenic epithelium embedded in cellular ectomesenchymal tissue that resembles the dental papilla and epithelial strands and varying degrees of inductive changes and dental hard tissue formation.” The tumor is most common in the first and second decades of life with a slight male predilection. The most common site is the posterior mandible and 75% of the cases are associated with an unerupted tooth. Radiologically, it may present as a unilocular or multilocular lesion. The treatment of choice could range from aggressive curettage for a small unilocular lesion to wide local excision for a large multilocular lesion. The prognosis is usually good, with a recurrence rate of approximately 20%. Here we present a case of a 13-year-old male with a multilocular expansile cystic lesion associated with nonvital tooth 20 and tooth 21 since 2016. An incisional biopsy was performed and the microscopic examination revealed small masses of cellular fibrous and myxoid connective tissue containing long narrow cords of odontogenic epithelium. The odontogenic islands were basophilic with peripheral nuclear palisading of the basal cell layer, consistent with an ameloblastic fibroma. Complete curettage was performed and the patient is being followed up with no recurrence since 2 months. We reviewed the literature with regard to clinical, histopathological, and radiological findings and reached the conclusion that malignant transformation of ameloblastic fibroma into ameloblastic fibrosarcoma is uncommon but well documented. AF needs to be distinguished from ameloblastoma and ameloblastic fibrosarcoma, since these two tumors can be locally invasive and have greater potential for recurrence than ameloblastic fibroma.