KERATOAMELOBLASTOMA OF THE MAXILLA - A CASE-REPORT AND REVIEW OF THE LITERATURE

The keratoameloblastoma is a rare histologic variant of the ameloblast oma. Review of the English language literature revealed five case. rep orts of keratoameloblastoma. We report the sixth case of this tumor. T he tumor developed in the right posterior maxilla of a 26-year-old Afr ican-American man and demonstrated aggressive clinical behavior, analo gous to conventional ameloblastoma. The initial biopsy specimen showed extensive cyst formation, which histologically resembled odontogenic keratocyst. However, the lining epithelium varied in thickness and the re was separation and edema between the basal cells and the rest of th e epithelium. The basal cells were strongly adherent to the underlying stroma unlike the basal layer of the odontogenic keratocyst, where cl eavage often occurs in this area. Additionally, although the basal cel ls were palisaded and demonstrated nuclear polarization in areas, they were cuboidal rather than columnar. The excision specimen revealed mo re of a solid ameloblastic component in addition to the cystic compone nt seen on the initial biopsy. Nevertheless, it is possible that the a meloblastoma had developed in an odontogenic keratocyst. Alternatively it can be postulated that the keratoameloblastoma consists of both cy stic and solid components, the former being analogous to the cysts of the conventional ameloblastoma.