RESUMEN
BACKGROUND: The fourth edition of the World Health Organization Classification of Head and Neck Tumors was published in January 2017, and includes a classification of odontogenic tumors and odontogenic cysts. The present review assesses the changes made in this new classification in relation to odontogenic and non-odontogenic jaw cysts. MATERIAL AND METHODS: An electronic search was conducted in the Cochrane Library, PubMed-MEDLINE and Scopus databases using the search terms: "odontogenic cyst" "WHO classification" "update". Studies written in English and published between January 2005 and April 2020 with a high level of scientific evidence were included, while studies not published in English, epidemiological studies, and studies with a low level of scientific evidence were excluded. RESULTS: The initial search identified 311 articles, and after the deletion of duplicates, 7 studies were selected for full-text assessment. After excluding two studies that failed to provide relevant information and had a low level of scientific evidence, 5 articles were finally included and stratified according to their level of scientific evidence based on the SORT (Strength of Recommendation Taxonomy) criteria. CONCLUSIONS: The incorporation of odontogenic and non-odontogenic cysts to the head and neck tumors classification underscores the recognition of the WHO of these important disorders of the jaws. Based on the current evidence, there is controversy as to whether odontogenic keratocysts should be regarded as cystic lesions or as neoplasms, though there is no such controversy in relation to calcifying odontogenic cysts. On the other hand, orthokeratinized odontogenic cysts have been included in the classification as a single entity differentiated from odontogenic keratocysts, while residual cysts have been removed from the classification. Key words:Odontogenic cyst, WHO classification, pseudocyst.
RESUMEN
BACKGROUND: The fourth edition of the WHO Classification of Head and Neck Tumours was published in January 2017 and includes a classification of odontogenic tumours. This review aims to examine the changes made in this new classification in comparison with the previous classification of 2005. MATERIAL AND METHODS: An electronic search was conducted in the PubMed, Scopus and Cochrane databases with the keywords odontogenic tumor, WHO classification and update. Studies published from January 2009 to April 2019 with a high level of scientific evidence were included, but studies not published in English, epidemiological studies and studies with a low level of evidence were excluded. RESULTS: The initial search found 457 articles and after eliminating duplicates, 8 studies were selected for full-text assessment. After excluding 3 epidemiological studies, 5 articles were finally included. These studies were stratified by their level of scientific evidence using SORT criteria (Strength of Recommendation Taxonomy). CONCLUSIONS: The new odontogenic tumour list has been simplified with the objective of improving its role as an international guide for diagnosis. Some changes have been possible thanks to the application of immunohisto-chemistry and molecular genetic techniques that allow better characterization of certain tumours. Further clinico-pathological and molecular studies are needed so that this new classification can be consolidated and/or amended
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