Optic nerve glioma

  • pilocytic astrocytoma occurring in childhood
  • involves optic nerves, chiasm and optic tracts
  • chiasmal lesions often extend to hypothalamus and is of a higher histological grade
  • associated with NF-1 (chiasmatic uncommon)
  • indolent clinical course
  • iso to hypointense of T1
  • hyperintense on T2
  • variable Gd+ enhancement
  • diffuse fusiform expansion of nerve can occur from subarachnoid dissemination