Peripheral ameloblastoma: use of cytokeratin 19 and Ber-EP4 to distinguish it from basal cell carcinoma

Rare tumor of the oral cavity presenting as a gingival swelling without bone involvement was present. The lesion, resected for mastication troubles, histologically presented a basaloid cell proliferation predominantly organized in nests formed by a peripheral palisading of cells with apically disposed nuclei. Immunohistochemical stainings for the cytokeratin 19 and Ber-EP4 showed a marked and diffuse positivity for the former, while the latter was negative. These results support the diagnosis of peripheral ameloblastoma and allow us to distinguish it from the basal cell carcinoma, which shares some histological features with this unusual tumor of the oral cavity.