title: Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Paragangliomas.
abstract: Updated editions of The World Health Organization Classification of Tumours Pathology & Genetics for both Head and Neck Tumours and Tumours of Endocrine Organs took place in 2016 based on consensus conferences. These editions present unification of concepts in paragangliomas and highlight expanding knowledge of their etiology. There is a major emphasis in the new bluebooks on familial/syndromic paragangliomas, representing ~40% of all head and neck paragangliomas. Ancillary use of immunohistochemical evaluation, specifically of SDHB, allows the pathologist to screen for a large subset of these potentially hereditary cases. In addition, similarly to other neuroendocrine tumors, paragangliomas are now considered to represent a continuum of risk, and are assessed in terms of risk stratification. Tumors with SDHB mutations pose the highest risk for metastasis. There is currently no validated or endorsed histologic grading system. Paragangliomas remain tumors of undetermined biologic potential and should not be termed benign.
authors.affiliation: Department of Pathology, Head and Neck Section, University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 085, Houston, TX, 77030, USA. mdwillia@mdanderson.org.
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Williams
authors.affiliation: Department of Pathology and Laboratory Medicine, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA.
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Tischler
mesh_terms: D006258:Head and Neck Neoplasms / Q000145:classification* / Q000473:pathology; D006801:Humans; D010236:Paraganglioma, Extra-Adrenal / Q000145:classification* / Q000473:pathology; D014944:World Health Organization
keywords: Carotid body tumor; Paraganglioma; Paraganglioma syndromes; SDHD; SDHx