Keratoameloblastoma of the Jaw Bones: Description of 2 Rare Cases and Cytokeratin Profile

Keratoameloblastoma is a rare keratinizing neoplasia characterized by ameloblastic differentiation, which histopathologically resembles an odontogenic keratocyst. In view of its expansive growth, surgical enucleation and resection are alternatives for treating keratoameloblastoma. The objective was to report 2 cases of keratoameloblastoma, highlighting their clinical, radiologic, and histopathologic features, as well as the immunohistochemical profile of cytokeratins. Clinicopathologic findings were described, and the cases were submitted to immunohistochemistry for cytokeratins (CK) 6, 7, 8, 10, 13, 14, 17, 18, 19, and Ki-67. Both cases involved the jaws of adult men. Histologically, they showed fibrous stromal tissue permeated by keratinizing follicular cysts that formed central parakeratin plugs, features resembled ameloblastoma, and cystic formations resembled an odontogenic keratocyst. Variable positive labeling for all cytokeratins studied was observed, except for CK8 and CK18, which were negative. The Ki-67 proliferation index was low. Keratoameloblastoma is an expansive neoplasm with a low proliferation index. The cytokeratin profile generally follows that of ameloblastomas and odontogenic keratocysts. Both cases are under follow-up and show no recurrence after 4 years.