Brain 17 Vienna

07.11.2017

H3 K27Mmutation

2016

What happened to Oligoastrocytoma?

• Defines a subgroup of diffuse intrinsic pontine gliomas • Mutation in histone protein -> epigenetic implications

BuczkowiczP etal,NatureGenetics2014

19

20

Oligoastrocytoma

Oligoastrocytoma

22

Oligodendroglioma

Astrocytoma

Difficulttodefine

High interobserver discordance

21

Oligoastrocytoma

Is genotype alone sufficient for diagnosis?

• Using phenotype & genotype (i.e., IDH mutation and 1p19q codeletion) allows to allocate them to either astrocytic or oligodendroglial subtypes • Discordant results of phenotype & genotype ->

• At this point in time: No

• WHO grading is still based on histologic criteria

genotype

• Challenges with respect to testing and reporting • Availability & choice of genotyping or surrogate genotyping assays

trumps histological phenotype!

• Introduction of „not otherwise specified, NOS“

23

24

4