Optic nerve sheath meningioma

Optic Nerve Sheath Meningioma

Radiation treatment for optic nerve sheath meningioma

Optic nerve sheath meningioma (ONSM) is a type of meningioma that arises from the meninges surrounding the optic nerve. It is a rare, benign tumor that can lead to progressive vision loss due to its location and effects on the optic nerve.

Pathophysiology

ONSM originates from the arachnoid cap cells of the meninges, which are the protective coverings of the central nervous system. These tumors are typically slow-growing and can cause compression of the optic nerve, leading to visual disturbances. The compression can result in optic atrophy and eventual loss of vision if not treated.

Clinical Presentation

Patients with optic nerve sheath meningioma often present with progressive, painless vision loss in one eye. Other symptoms may include proptosis (bulging of the eye), diplopia (double vision), and optic disc swelling.

Diagnosis

The diagnosis of ONSM is primarily made through imaging studies. Magnetic resonance imaging (MRI) is the preferred method, as it provides detailed images of the optic nerve and surrounding structures. On MRI, ONSM typically appears as a tubular thickening around the optic nerve.

MRI showing optic nerve sheath meningioma

Treatment

The management of optic nerve sheath meningioma depends on the size and location of the tumor, as well as the degree of vision loss. Observation may be appropriate for small, asymptomatic tumors. However, for tumors causing significant vision loss, treatment options include radiation therapy and, in some cases, surgical intervention.

Radiation therapy, particularly stereotactic radiosurgery, is often the treatment of choice for ONSM, as it can effectively control tumor growth and preserve vision.

Prognosis

The prognosis for patients with optic nerve sheath meningioma varies. Early detection and treatment are crucial for preserving vision. While the tumor itself is benign, its location can lead to significant morbidity if not managed appropriately.

Related Pages

• Optic nerve
• Meningioma
• Vision loss
• Proptosis

See Also

• Neuro-ophthalmology
• Benign tumor
• Stereotactic radiosurgery