Characteristics, Diagnosis, and Treatment of Optic Nerve Sheath Meningioma, the Most Common Optic Nerve Tumor in Adults

👁 Optic Nerve Sheath Meningioma – Most Common Optic Tumor in Adults

Optic nerve sheath meningioma (ONSM) is a benign tumor arising from the arachnoid layer of the meninges surrounding the optic nerve.
While rare overall, it is the most common optic tumor in adults, especially middle-aged women.

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✅ Origin & Pathophysiology

• Originates from arachnoid villi in the optic nerve sheath
• Meningiomas can also arise from sphenoid bone meningeal surfaces, invading the orbit secondarily
• Growth is slow, often leading to delayed diagnosis

 

 

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✅ Clinical Features

FeatureDescription

Onset	Gradual over months to years
Symptoms	Progressive visual loss → proptosis
Pain	Absent
Laterality	Often unilateral
Visual field loss	Due to nerve compression

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✅ CT & MRI Findings

• Railroad tracking or tram-track sign seen on imaging
• Calcification seen in 25%
• Thickening along the optic nerve sheath

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✅ Comparison to Optic Glioma

CategoryOptic GliomaOptic Nerve Sheath Meningioma

Age group	Children	Adults
Origin	Optic nerve	Optic nerve sheath
Growth	Rapid	Slow
Diagnosis timing	Early	Often delayed
Treatment	Surgery/radiation	Radiation ± surgery

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✅ Management

ConditionApproach

No vision loss	Observation
Vision loss only	Radiotherapy
Intracranial spread	Surgery ± Chemotherapy