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Meningiomas
Now designated as a single biological entity graded 1 to 3 based on histopathology and specific molecular criteria.
Subtypes3
Grade Range
G1G2G3
Subtypes
Grade 1 Meningioma
WHO Grade 1
Accounts for ~80%. Subtypes include Meningothelial, Fibrous, Transitional, Psammomatous.
Diagnostic Molecular Markers
KLF4/TRAF7 (secretory subtype)
Locations:
Grade 2 Meningioma (Atypical)
WHO Grade 2
Defined by >=4 mitoses/10 HPF or 3/5 specific histologic criteria.
Locations:
Grade 3 Meningioma (Anaplastic)
WHO Grade 3
Sui Generis Grade 3 regardless of histology if TERT or CDKN2A/B altered. Or based on >=20 mitoses.
Diagnostic Molecular Markers
TERT promoter mutationHomozygous CDKN2A/B deletion
Locations:
Primary Locations
Clinical Note
Grading and diagnostic criteria listed here are based strictly on the 2021 WHO Classification of Tumours of the Central Nervous System (5th Edition). Many entities now require integrated phenotypic and genotypic characterization for a final diagnosis.