Ameloblastic fibrodentinoma (AFD) is considered a mixed odontogenic tumor that is characterized by conserved epithelial and ectomesenchymal neoplastic components. AFD is composed of long narrow cords and islands of odontogenic epithelium; the epithelial strands lie in a myxoid cell-rich ectomesenchymal tissue with stellate-shaped fibroblasts that exhibit long slender cytoplasmic extensions that resemble dental papilla. The lesions show the presence of dysplastic dentin. Although AFD is a rare entity and its very existence is not completely accepted, based on the extent of histodifferentiation, it is considered to represent a stage between ameloblastic fibroma and ameloblastic fibroodontoma. This study aimed to provide a histopathological and immunohistochemical characterization of this infrequent tumor. A large panel of antibodies including amelogenin, Ck 19, calretinin, syndecan-1, E-cadherin, MSH2, histone H3, and Ki-67 was used to illustrate the nature of the tumor. 1. Introduction Odontogenic tumors (OT) are lesions that are derived from the tooth-producing tissues or their remnants that remain entrapped either within the jawbones or within the adjacent soft tissues. From a biological standpoint, some of these lesions represent hamartomas that exhibit varying degrees of differentiation, whereas others are benign or malignant neoplasms that exhibit variable aggressiveness and a potential to develop metastasis [1]. Ameloblastic Fibrodentinoma (AFD) is considered as “very low frequency” tumor. This rare neoplasm represents less than 1% of all odontogenic tumors in most of the published literature worldwide [1]. Histopathologically, AFD is comprised of an odontogenic ectomesenchyme that resembles the dental papilla and epithelial strands and nests that resemble the dental lamina and enamel organ with the presence of dentin formation. Occasionally, this odontogenic tumor might be associated with an unerupted tooth, presenting as a slow-growing asymptomatic swelling in the posterior mandible. The age at diagnosis generally falls within the first two decades of life [2]. Treatment consists of enucleation and curettage. Although recurrence is a possibility, it does not justify initial aggressive treatment. AFD rarely progresses to malignancy as ameloblastic fibrodentinosarcoma [3]. The aim of this study was to histopathologically and immunohistochemically characterize this rare tumor using a large panel of antibodies. We furthermore discuss the possible implications or functions that each protein might contribute to the biological behavior of this uncommon
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