Ameloblastoma of the jaws.

Ameloblastoma is a histologically benign tumor derived from odontogenic apparatus. The tumor can infiltrate into surrounding tissues. Although it is benign, it presents symptoms of a malignant tumor, such as infiltration into the lungs, pleura, regional and distant metastases, orbit, base of skull, brain and has resulted in death. It also has a high incidence of recurrences, the existence of regional or distant metastasis, showing a microscopic pattern of ameloblastic carcinoma with cytologic features of an increasing nuclear/cytoplastic ratio, nuclear hyperchromatism, and the presence of mitosis. We report a study of 12 patients of ameloblastoma of the jaws between January 1992 and December 1996 consisting of 8 affected in the mandible and 4 in the maxilla. One patient with a tumor in the maxilla was excluded from this study, due to a different histological and clinical behaviour of the ameloblastoma.