Cystic ameloblastoma. A clinicopathologic analysis.

Thirty-three cases of ameloblastoma arising from odontogenic cyst linings are presented. Lesions of this nature have been referred to as "unicystic ameloblastoma." Our data support the findings of others in that this lesion differs from the solid invasive varieties of ameloblastoma, as the former occurs in a younger age group and exhibits a low rate of recurrence following enucleation or curettage. On the basis of histopathologic features we provide evidence that these lesions represent mural and luminal ameloblastomatous change in a pre-existing cyst rather than cystic degeneration of a solid tumor.