AMELOBLASTOMA: REVIEW OF 34 CASES

¹ Registry of Dental and Oral Pathology of the American Dental Association, Army Medical Museum, Washington, D. C.

In this review of 34 cases of ameloblastoma one is impressed with the extreme variability of the histology of this tumor. To arbitrarily list it as either solid or cystic does not seem warranted insofar as the greater percentage of lesions seems to be in the stage of transition between these two extremes. The findings as to the age of discovery, the age at time of report, and duration are in agreement with the statistics reported by other authors.

It is important to recognize that the ameloblastoma, while it may have malignant potentialities as evidenced histologically, is essentially benign in its clinical behavior. An appreciable percentage of these tumors will show epidermoid tendencies up to a certain point. However, metastasis is an uncommon occurrence. In those cases in which this has been reported, reviewed by me, the ameloblastic features were lacking.

There seems little conclusive evidence for associating this tumor with the well differentiated basal cell carcinoma. While these lesions may have a common point of origin, the germinal layer, and certain other similar growth characteristics, they are still essentially different tumors. One cannot depend entirely upon the cell morphology, ignoring the clinical features.

Recurrence in this lesion is an important consideration. The belief of McFarland that mixed tumors of salivary gland origin are more easily removed in their entirety when the lesion has reached an appreciable size seems applicable to the ameloblastoma. In those cases in which too much bony structure has not been [see table in the pdf file] destroyed the chances for complete removal are greater if the lesion is sufficiently large to permit satisfactory operative procedure.

The ameloblastoma, contrary to the belief of many, is not necessarily a painless lesion. This is undoubtedly because its most usual site of occurrence is at the angle of the ramus and the body of the mandible where it may easily become secondarily infected. The presence of a suppurative inflammatory process may influence somewhat the reactivity of the component of the tumor resulting in a pseudo-epitheliomatous hyperplasia.

The incidence of an inflammatory reaction within the tumor mass was sufficiently high in this group to mark it as an almost constant occurrence. In some instances the exudate was scanty, and predominantly chronic in character. The age of the fibrous tissue component of these tumors varies proportionately with the age of the tumor. In those of long standing considerable collagen is produced which tends to diminish the vascularity in these areas.