Logic and clinical significance of the new WHO classification of ameloblastoma in 2017

A substantial revision of the classification of ameloblastoma was made by the World Health Organization (WHO) in the fourth edition of the Classification of Head and Neck Tumors in 2017, which was based on the review and summary of much clinical research data and prospective evaluation of the latest results of genetic research. The new classification is simpler and more practical. It retains two subtypes, the unicystic type and extraosseous/peripheral type, classifies the remaining types as ameloblastoma (classic), defines metastatic ameloblastoma as a benign tumor and simplifies the classification of ameloblastic carcinoma, which has important guiding significance for clinical diagnosis and treatment. Moreover, the new classification included the latest advances in the genetic research on ameloblastoma, demonstrating that the BRAF gene mutation was found in approximately 60% of ameloblastoma cases. The classification provides a new concept and direction for studying the pathogenesis of ameloblastoma, and BRA