title: International Society Of Neuropathology--Haarlem consensus guidelines for nervous system tumor classification and grading.
abstract: Major discoveries in the biology of nervous system tumors have raised the question of how non-histological data such as molecular information can be incorporated into the next World Health Organization (WHO) classification of central nervous system tumors. To address this question, a meeting of neuropathologists with expertise in molecular diagnosis was held in Haarlem, the Netherlands, under the sponsorship of the International Society of Neuropathology (ISN). Prior to the meeting, participants solicited input from clinical colleagues in diverse neuro-oncological specialties. The present "white paper" catalogs the recommendations of the meeting, at which a consensus was reached that incorporation of molecular information into the next WHO classification should follow a set of provided "ISN-Haarlem" guidelines. Salient recommendations include that (i) diagnostic entities should be defined as narrowly as possible to optimize interobserver reproducibility, clinicopathological predictions and therapeutic planning; (ii) diagnoses should be "layered" with histologic classification, WHO grade and molecular information listed below an "integrated diagnosis"; (iii) determinations should be made for each tumor entity as to whether molecular information is required, suggested or not needed for its definition; (iv) some pediatric entities should be separated from their adult counterparts; (v) input for guiding decisions regarding tumor classification should be solicited from experts in complementary disciplines of neuro-oncology; and (iv) entity-specific molecular testing and reporting formats should be followed in diagnostic reports. It is hoped that these guidelines will facilitate the forthcoming update of the fourth edition of the WHO classification of central nervous system tumors.
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: David N
authors.initials: DN
authors.lastname: Louis
authors.forename: Arie
authors.initials: A
authors.lastname: Perry
authors.forename: Peter
authors.initials: P
authors.lastname: Burger
authors.forename: David W
authors.initials: DW
authors.lastname: Ellison
authors.forename: Guido
authors.initials: G
authors.lastname: Reifenberger
authors.forename: Andreas
authors.initials: A
authors.lastname: von Deimling
authors.forename: Kenneth
authors.initials: K
authors.lastname: Aldape
authors.forename: Daniel
authors.initials: D
authors.lastname: Brat
authors.forename: V Peter
authors.initials: VP
authors.lastname: Collins
authors.forename: Charles
authors.initials: C
authors.lastname: Eberhart
authors.forename: Dominique
authors.initials: D
authors.lastname: Figarella-Branger
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Fuller
authors.forename: Felice
authors.initials: F
authors.lastname: Giangaspero
authors.forename: Caterina
authors.initials: C
authors.lastname: Giannini
authors.forename: Cynthia
authors.initials: C
authors.lastname: Hawkins
authors.forename: Paul
authors.initials: P
authors.lastname: Kleihues
authors.forename: Andrey
authors.initials: A
authors.lastname: Korshunov
authors.forename: Johan M
authors.initials: JM
authors.lastname: Kros
authors.forename: M
authors.initials: M
authors.lastname: Beatriz Lopes
authors.forename: Ho-Keung
authors.initials: HK
authors.lastname: Ng
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ohgaki
authors.forename: Werner
authors.initials: W
authors.lastname: Paulus
authors.forename: Torsten
authors.initials: T
authors.lastname: Pietsch
authors.forename: Marc
authors.initials: M
authors.lastname: Rosenblum
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Rushing
authors.forename: Figen
authors.initials: F
authors.lastname: Soylemezoglu
authors.forename: Otmar
authors.initials: O
authors.lastname: Wiestler
authors.forename: Pieter
authors.initials: P
authors.lastname: Wesseling
mesh_terms: D006801:Humans; D025202:Molecular Diagnostic Techniques; D009423:Nervous System Neoplasms / Q000145:classification* / Q000175:diagnosis*; D012720:Severity of Illness Index
keywords: Astrocytoma; World Health Organization; atypical teratoid rhabdoid tumor; brain tumors; classification; glioblastoma; glioma; grading; medulloblastoma; oligodendroglioma