Pediatric Optic Pathway Glioma

  • Etiology: Proliferation of well differentiated astrocytes leads to low grade glial neoplasm
  • Imaging:
    — Tubular or fusiform enlargement of optic nerve
    — 60-70% have posterior extension along optic tracts leading to non-resectability
    — Rare to have calcifications
    — Optic pathway tumors in patients with neurofibromatosis Type 1 often involve optic nerves and tend to be low signal on T2WI and may show no or heterogeneous enhancement
    — Optic pathway tumors in patients without neurofibromatosis Type 1 have increased signal on T2WI, intense homogenous enhancement, involve chasm more, cysts more commonly present
  • DDX: Optic nerve sheath meningioma – peripheral, may be dark on T2WI (optic pathway glioma is bright on TW2I), can have calcification, enhances intensely (versus less or no enhancement for optic pathway glioma)
  • Complications:
  • Treatment:
  • Clinical:
    — Chiasmatic or hypothalamic glioma usually presents before 4 years with visual problems or hypothalmic dysfunction
    — Majority of tumors are juvenile pilocystic astrocytomas
    — Most common cause of optic nerve enlargement
    — 80% of primary tumors of optic nerve
    — Age – 80% in first decade, peak age 5 years old
    — 15% of neurofibromatosis Type 1 patients have optic pathway glioma
    — 10-50% of optic pathway glioma patients have neurofibromatosis Type 1

Radiology Cases of Optic Pathway Glioma

MRI of optic pathway gliomas in neurofibromatosis type I
Axial (left) and coronal T1 MRI with contrast of the orbits shows marked thickening of the optic nerves bilaterally.
MRI of macrophtalmia and optic pathway glioma in neurofibromatosis type I
Axial (above) and coronal (below) T2 MRI without contrast of the brain shows the left globe is larger than the right globe. The optic nerves bilaterally are thickened and tortuous.