Optic nerve glioma

A type of brain tumor affecting the optic nerve

Classification
External resources

Overview

Optic nerve glioma as seen on MRI

An optic nerve glioma is a type of brain tumor that affects the optic nerve, which is responsible for transmitting visual information from the eye to the brain. These tumors are typically slow-growing and are most commonly found in children, particularly those with neurofibromatosis type 1 (NF1).

Pathophysiology

Optic nerve gliomas are classified as gliomas, which are tumors that arise from glial cells in the central nervous system. Specifically, they are often pilocytic astrocytomas, a type of low-grade glioma. The tumor can cause progressive vision loss due to its location on the optic nerve, and it may also lead to other neurological symptoms if it extends into the optic chiasm or other nearby structures.

Symptoms

The symptoms of an optic nerve glioma can vary depending on the size and location of the tumor. Common symptoms include:

• Progressive vision loss in one or both eyes
• Proptosis, or bulging of the eye
• Strabismus, or misalignment of the eyes
• Nystagmus, or involuntary eye movements
• Headache
• Nausea and vomiting if the tumor causes increased intracranial pressure

Diagnosis

MRI scan showing optic nerve glioma

Diagnosis of an optic nerve glioma typically involves a combination of clinical evaluation and imaging studies. Magnetic resonance imaging (MRI) is the preferred method for visualizing the tumor and assessing its extent. An ophthalmological examination may also be conducted to evaluate the impact on vision.

Treatment

The treatment of optic nerve glioma depends on several factors, including the age of the patient, the size and location of the tumor, and the presence of symptoms. Treatment options may include:

• Observation: In cases where the tumor is not causing significant symptoms, regular monitoring with MRI may be recommended.
• Surgery: Surgical removal of the tumor may be considered if it is causing significant symptoms or if there is a risk of further vision loss.
• Radiation therapy: This may be used in cases where surgery is not feasible or if the tumor recurs after surgery.
• Chemotherapy: This is often used in children, especially those with NF1, to shrink the tumor and preserve vision.

Prognosis

The prognosis for patients with optic nerve glioma varies. In general, these tumors have a relatively good prognosis, especially in children with NF1, where they tend to be less aggressive. However, the potential for vision loss remains a significant concern, and long-term follow-up is necessary.

Related pages

• Neurofibromatosis type 1
• Glioma
• Optic nerve
• Brain tumor