Journal of Prevention and Treatment for Stomatological Diseases ›› 2020, Vol. 28 ›› Issue (7): 416-420.doi: 10.12016/j.issn.2096-1456.2020.07.002

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

TAO Qian(),YANG Yaocheng   

  1. Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China
  • Received:2019-06-18 Revised:2020-01-30 Online:2020-07-20 Published:2020-06-04
  • Contact: Qian TAO E-mail:taoqian@mail.sysu.edu.cn

Abstract:

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 BRAF-targeted therapy may be an emerging therapy for some ameloblastoma patients with multiple recurrence or surgical contraindications. This article analyzes the intrinsic logic of these changes via a review of the relevant literature and combination of clinical experiences to better understand the new classification. In 2017, the WHO′s new classification of ameloblastoma summarized the experience and achievements in histopathology and clinical treatment of ameloblastoma in the prior 10 years, indicating that BRAF-targeted treatment may bring new treatment options and hope for patients with recurrent or inoperable ameloblastoma.

Key words: ameloblastoma, metastatic ameloblastoma, benign odontogenic tumor, odontogenic epithelial origin, pathology, genetics, classification, BRAF gene mutation, molecular targeted therapy, World Health Organization

CLC Number: 

  • R78

Table 1

Four editions of WHO classification of benign/malignant ameloblastoma"

2017[5](The 4th edition) 2005[4](The 3rd edition) 1992[3](The 2nd edition) 1971[2](The 1st edition)
Benign
Ameloblastoma
Ameloblastoma, extrasseous/peripheral type
Ameloblastoma, unicystic type
Metastasizing ameloblastoma
Ameloblastoma, solid/multicystic type
Ameloblastoma, extrasseous/peripheral type
Ameloblastoma, desmoplastic type
Ameloblastoma, unicystic type
Ameloblastoma


Ameloblastoma


Malignant
Ameloblastic carcinoma




Malignant(metastazing) ameloblastoma
Ameloblastic carcinoma, primary type
Ameloblastic carcinoma, secondary type (dedifferentiated), intrasseous
Amelobastic carcinoma, secondary type (dedifferentiated), peripheral
Malignant ameloblastoma



Ameloblastic carcinoma



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