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Embryonal Tumors
Highly malignant, small round blue cell neoplasms of early childhood, predominantly located in the posterior fossa.
Subtypes3
Grade Range
G4
Subtypes
Medulloblastoma, WNT-activated
WHO Grade 4
Subgroup with the best prognosis (>95% cure).
Diagnostic Molecular Markers
CTNNB1 mutationMonosomy 6
Locations:
Medulloblastoma, SHH-activated
WHO Grade 4
Can be TP53-mutant (poor prognosis) or wildtype. Desmoplastic/nodular histology is common.
Diagnostic Molecular Markers
PTCH1, SUFU, SMO mutationsTP53 (mutant or wildtype)
Locations:
Atypical teratoid/rhabdoid tumor (AT/RT)
WHO Grade 4
Highly aggressive infantile tumor. Can occur in posterior fossa or supratentorially.
Diagnostic Molecular Markers
Loss of SMARCB1 (INI1) or SMARCA4
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.