A histopathologic study of 116 ameloblastomas with special reference to the desmoplastic variant.

The histopathologic features of 116 ameloblastomas were reviewed with special reference to the incidence of the recently described desmoplastic variant. The series included 110 intraosseous lesions and 6 extraosseous ameloblastomas. Ninety-six (88%) of the intraosseous tumors were found in the mandible, and 61% involved the molar-ascending ramus area. Fourteen examples of the desmoplastic variant were identified, representing 13% of the intraosseous tumors. The lesions showed distinctive histologic features characterized by an extensive collagenized stroma containing small islands of tumor epithelium with scant tendency to form cystic structures. This histologic variant has a marked tendency to involve the anterior portions of the jaws with 7 of the 14 examples being located in the maxilla. These desmoplastic lesions also showed unusual radiographic findings, often more suggestive of a benign fibro-osseous lesion than of ameloblastoma.