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Low-grade epilepsy-associated neuroepithelial tumours — the 2016 WHO classification

Abstract

Rapid developments in molecular genetic technology and research have swiftly advanced our understanding of neuro-oncology. As a consequence, the WHO invited their expert panels to revise the current classification system of brain tumours and to introduce, for the first time, a molecular genetic approach for selected tumour entities, thus setting a new gold standard in histopathology. The revised 5th edition of the 'blue book' was released in May 2016 and will have a major impact in stratifying diagnosis and treatment. However, low-grade neuroepithelial tumours that present with early-onset focal epilepsy and are mostly seen in children and young adults (previously designated as long-term epilepsy-associated neuroepithelial tumours, LEAT) lack such innovative clinicopathological and molecular genetic tools. The Neuropathology Task Force of the International League against Epilepsy will critically discuss this issue, and will offer perspectives on how to decipher and validate clinically meaningful LEAT entities using the current WHO approach that integrates clinicopathological and genetic classification systems.

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Figure 1: Is it all in one? The histopathological spectrum of nodular growth in low-grade epilepsy-associated neuroepithelial tumours.
Figure 2: Molecular genetic pathways affected in low-grade epilepsy-associated neuroepithelial tumours.
Figure 3: Roadmap to comprehensive clinicopathological and genetic WHO–ILAE classification of epilepsy-associated neuroepithelial tumours.

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Acknowledgements

Members of the ILAE Neuropathology Task Force have been partially supported by the Seventh Framework Programme of the European Commission (DESIRE GA # 602531 to I.B.; EPITARGET GA # 602102 to A.B., and E.A.; EPISTOP # 602391 to E.A.). E.A. has received funding from KIKA (Stichting Kinderen Kankervrij) and Stichting AMC Foundation. T.J. has received funding from the Brain Tumour Charity, Children with Cancer, Great Ormond Street Children's Charity and NIHR. H.M. has received funding from the Japan Epilepsy Research Foundation (JERF) (H25-003).

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Blümcke, I., Aronica, E., Becker, A. et al. Low-grade epilepsy-associated neuroepithelial tumours — the 2016 WHO classification. Nat Rev Neurol 12, 732–740 (2016). https://doi.org/10.1038/nrneurol.2016.173

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