pilocytic astrocytoma


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  • Clinical

    • NF1 association (bilateral optic nerve glioma)
    • young age, most common pediatric glioma
    • 5% of all glioma
    • 67% in cerebellum
    • other sites: optic nerve, hypothalamus, thalamus
    • WHO grade I
  • Histology

    • hair like projections on smear
    • Rosenthal fibers, eosinophilic granular bodies
    • biphasic: cellular and loose/microcystic areas
    • can have high grade foci and oligodendroglioma-like areas
      • mitosis
      • atypia, pleomorphism
      • microvascular proliferation
      • necrosis
      • meningeal infiltration
  • Stains

    • GFAP+ in cellular areas
    • Ki67 < 5%
  • Molecular

    • NF1 association