Optic Nerve Sheath Lesion

Bernadette L. Koch, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Helpful Clues for Common Diagnoses

Optic Neuritis
- Key facts: Inflammatory, autoimmune, infectious, post-radiation
  - Acute vision loss, unilateral (70%)
- Imaging: Enhancement, minimal enlargement, focal or diffuse
Optic Pathway Glioma
- Key facts: Pilocytic astrocytoma
  - 30-40% have neurofibromatosis type 1
  - Imaging: Tubular enlargement and tortuosity of intraorbital optic nerve
  - Optic nerve, chiasm, tract &/or optic radiations, variable enhancement

Helpful Clues for Less Common Diagnoses

Idiopathic Orbital Inflammatory Disease (Pseudotumor)
- Key facts: Painful, anterior subtype of IOID
  - Isolated or with other subtypes of IOID (myositic, lacrimal, diffuse, or apical)
- Imaging: Irregular nerve sheath thickening and enhancement
Lymphoproliferative Lesions, Orbit
- Key facts: Leukemia or lymphoma (low-grade small B-cell, large B-cell, Burkitt, or T-cell)
- Imaging: Optic nerve sheath/complex enhancement ± solid mass anywhere in orbit
Sarcoidosis, Orbit
- Key facts: Noncaseating granulomas
  - Lacrimal gland, EOMs, optic nerve/sheath complex, intraconal/extraconal space, or uvea/sclera
- Imaging: Enhancing soft tissue mass or enlargement and enhancement of any involved orbital structure

Helpful Clues for Rare Diagnoses