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New risk stratification since 2016
Kuzan-Fischeretal,ClinicalNeurosurgery,2017
37
Other embryonal tumors
38
• Dismissal of PNET, primitive neuroectodermal tumor
• Instead:
•
C19MC
-amplified Embryonal tumor with multilayered rosettes
• ETANTR + ependymoblastoma + medulloepithelioma
• Immunohistochemical marker LIN28
•
Atypical teratoid/rhabdoid tumor (AT/RT)
• defined by
INI1
or very rarely
BRG1
• Immunohistochemical marker SMARCB1/INI1
• Wastebasket category for all others: CNS embryonal tumor, NOS
Other tumors: Ependymoma
39
• WHO grading of unclear clinical significance
• One narrowly defined subgroup: Ependymoma, RelA gene fusion
• Drives NFkappaB signaling (outside of the mutation box!)
• Majority of supratentorial tumors in children, poor prognosis!
• L1CAM expression as immunohistochemical surrogate
New diagnostic entity
MParker
et al.Nature
(2014)
Neuronal and mixed neuronal-glial tumors
40
Diffuse leptomeningeal glioneuronal tumor
• Mostly in children
and adolescents
• Histologically
reminiscent of
oligodendroglioma
New diagnostic entity
BRAF-KIA gene fusion
1p del
Louiset al,
Acta Neuropath 2016
Meningioma
41
• Classification and grading not revised
• Except:
brain invasion
as a criterion for atypical meningioma, WHO
grade II
• Mitotic count (5 mitoses per 10 high-power fields) or
• Brain invasion is sufficient
Brain invasion
Mitotic count
NEW
Solitary fibrous tumor - hemangiopericytoma
42
• Soft tissue pathologists moved away from the designation
hemangiopericytoma
• Considered within the spectrum of solitary fibrous tumors
• Both share genetic constellations, most notably
STAT6
gene fusion
-> one common entity
• Grade I-III
• Grade I: highly collagenous, low cellularity
• Grade II: more cellular, less collagenous „staghorn“ vessels
• Grade III: + 5 mitoses per 10 high-power fields