Ameloblastomas: current aspects of the new WHO classification in an analysis of 136 cases

Abstract

Ameloblastomas are neoplasms that have inspired great controversy and clinical interest; their incidence, radiographic features, treatment and behavior are still discussed quite often in the literature. In 2017, the classification of these lesions underwent modifications in terminology with the introduction of prospective views based on updates in current genetic studies. To describe the most important features of the new classification, as well as to evaluate the prevalence and the clinical and radiographic characteristics of 136 ameloblastomas. The clinical-pathological characteristics of 136 patients diagnosed with ameloblastoma in two large hospitals in São Paulo were analyzed. All the hematoxylin-eosin (HE) stained slides were reviewed using an optical microscope (Olympus Cover) and tumors were classified according to the new WHO criteria (2017). Two independent evaluators analyzed the slides; in cases where there was disagreement a third evaluator was used and the result was established in consensus. 71% of the lesions were of the conventional type, the predominant histopathological pattern being plexiform (40%), 72% of the tumors showed cortical expansion, and 84% had a radiographic pattern of the multilocular type. The treatment of choice in most cases was segmental resection (45%) and recurrence was present in 13% of the cases. Studies with clinical-pathological correlations will be necessary in the near future, in order to provide new therapies that are more effective and conservative, improving the quality of life of patients effected.