Optic nerve glioma

Case contribution: Dr Radhiana Hassan

Clinical:

  • A 20 years old male
  • No known medical illness
  • Presented with left eye blindness and ptosis
  • No headache, no fever no constitutional symptom
MRI orbit in axial planes
MRI orbit in coronal planes

MRI findings:

  • There is left proptosis.
  • A heterogenous mass with solid and cystic component is seen in the intraconal region of the left orbit (yellow arrows).
  • There is enhancement of the solid component post contrast and rim enhancement of the cystic component.
  • This mass extends posteriorly, enlarging the left optic foramen.
  • No involvement of optic chiasm.
  • The recti muscles are in close proximity to the mass.
  • The right orbit and contents are normal.

Diagnosis: Optic nerve glioma (HPE proven)

Discussion:

  • Optic nerve glioma is part of optic pathway glioma
  • They are the most common primary neoplasm of the optic nerve
  • Histologically these tumours are pilocytic astrocytomas
  • Typically present in children, adult forms are rare and usually aggressive
  • CT is often the first investigation performed and although not as sensitive as MRI.
  • The optic nerve is variably enlarged, and the mass may either be fusiform or exophytic in appearance.¬†Additionally, the nerve may be elongated with kinking or buckling¬†5.
  • MR imaging is optimal for showing the relationship of the mass to the hypothalamus, optic chiasm, and infundibulum as well as the intraorbital and intercanalicular components of the mass.
  • Large tumors are typically heterogeneous with cystic and solid components.
    • T1 enlargement, often iso to hypointense compared to the contralateral side
    • T2hyperintense centrally, thin low-signal at the periphery representing the dura
    • T1 C+ (Gd)enhancement is variable
Author: radhianahassan