Peripheral ameloblastoma with neoplastic osseous invasion versus peripheral intraosseous ameloblastoma: A challenging...

Peripheral ameloblastoma, a soft-tissue analogue of intraosseous ameloblastoma, is a rare odontogenic tumor with histologic characteristics of ameloblastoma. In contrast to conventional ameloblastoma, peripheral ameloblastomas are considered as innocuous lesions which usually do not show invasion of the underlying structures. Rarely, intraosseous ameloblastoma which penetrates the alveolar bone can fuse with the overlying oral epithelium and eventually manifest as an exophytic peripheral lesion. Such lesions which mimic peripheral ameloblastoma both clinically and microscopically are termed as peripheral intraosseous ameloblastoma. As per the existing criteria, soft-tissue ameloblastomas showing bone invasion are strictly excluded from the category of peripheral ameloblastoma and are considered as peripheral intraosseous ameloblastoma. We report a rare case of extraosseous ameloblastoma with clear origin from the superficial epithelium showing the presence of a few odontogenic islands in the underlying bone suggestive of a neoplastic osseous invasion. This paper discusses the diagnostic challenges associated with peripherally occurring ameloblastomas and stresses the need for accurate diagnosis in deciding the treatment modalities.