Pathological Features of Common Pediatric Brain Tumors

The 2021 revision of the WHO Guide to CNS tumors included major revisions to the diagnostic classification of pediatric brain tumors, including the clear differentiation between adult and pediatric-type gliomas, the incorporation of genetically and anatomically defined subgroups of ependymoma, and the inclusion of novel embryonal tumor entities. Molecular testing, including for genetic driver mutations, copy number alterations, and methylation profiles has taken an increasingly important role in the diagnostic and grading criteria for many tumor types. In this chapter, we summarize the most common pediatric brain tumors, highlighting the important diagnostic features and differential diagnoses, as well as the changes in the diagnostic framework.