الورم الدِبقي في العصب البصري

نظرة عامة

An optic glioma is a tumor that forms along the nerves that carry information from the eyes to the brain. It most often involves the optic nerve, which connects the eye to the brain. The tumor also can involve the area where the optic nerves from each eye cross near the center of the brain. Optic gliomas also are called optic pathway gliomas.

Terms such as optic nerve tumor or optic nerve glioma are often used to describe tumors that form along the same optic pathway. These terms generally refer to optic gliomas.

Optic gliomas occur more often in people with neurofibromatosis type 1 (NF1), a genetic condition that affects how nerve and brain cells grow. Even so, an optic glioma is not a neurofibroma. Neurofibromas grow on nerves outside the brain, while optic gliomas form within the brain and optic nerves. Optic gliomas also can develop in people who do not have NF1.

Most optic gliomas develop in childhood and tend to grow slowly. This means they're considered low-grade tumors. Even when they are low grade, they can still affect vision or nearby brain areas because of their location.

In adults, optic gliomas are rare. When they do occur, they are more likely to be aggressive and grow more quickly. Because of this difference, age is an important factor in understanding how an optic glioma might behave, the likely prognosis and how it is treated.

الأعراض

Symptoms of an optic glioma vary depending on where the tumor is located along the visual pathway and whether nearby brain structures are affected. Because optic gliomas grow along the visual pathway, they can damage the optic nerve and affect vision. In adults, optic pathway tumors may grow more quickly and place pressure on the optic nerve or nearby brain structures, leading to faster changes in vision.

Vision changes are the most common symptoms and may include:

• Blurred vision.
• Reduced vision in one or both eyes.
• Loss of part of the visual field, such as difficulty seeing objects to the side.
• Trouble with visual tracking or recognizing objects, especially in young children.
• Eyes that do not line up or move together, especially in young children.

People may have different symptoms based on the tumor's location:

• Tumors affecting the optic nerve behind one eye may cause gradual vision loss in that eye or visible bulging of the eye.
• Tumors involving the area where the optic nerves cross may affect vision in both eyes and make it harder to see to the sides.
• Tumors that increase pressure in the brain may cause headache, nausea or vomiting. Pain other than headache is uncommon with optic glioma.

If an optic glioma spreads into nearby parts of the brain that control hormones or other body functions, additional symptoms may include:

• Early puberty or other hormone-related changes, especially in children.
• Changes in growth or weight.
• Weakness or trouble with balance.
• Changes in behavior or development.

Symptoms in children and adults

Optic gliomas most often affect children, and symptoms in children may be hard to notice at first. Vision changes may not be noticed, especially in younger children who cannot describe what they see. Adults rarely develop optic pathway tumors, but when they do, symptoms are more likely to appear quickly and may worsen over a shorter period of time. Because of these differences, symptoms are often monitored differently in children and adults.

Some optic gliomas cause few symptoms and may stay the same for a long time. When symptoms are mild or not present, they may be regularly monitored.

When to seek care 

Vision changes should be checked promptly, especially in children, since optic gliomas often affect vision before other symptoms appear. See your healthcare professional if any of the following happen:

• Blurred vision or trouble seeing clearly.
• Vision loss in one or both eyes.
• Trouble seeing to the sides.
• Eyes that do not line up or move together.
• A bulging or swollen appearance of one eye.

Children may not be able to describe vision changes. A checkup is important if a child shows signs such as:

• Poor tracking of objects.
• Bumping into objects more often.
• Delayed visual development.
• New or worsening eye misalignment.

Seek care more urgently if symptoms suggest increased pressure in the brain or involvement of nearby brain areas, including:

• Persistent or worsening headache.
• Nausea or vomiting not related to illness.
• Rapid changes in vision.
• Early puberty or other hormone-related changes that are not expected.
• Weakness, behavior changes or trouble with balance.

People with neurofibromatosis type 1 (NF1) should have regular eye exams even if they don't have symptoms.

الأسباب

The exact cause of most optic gliomas is not known. These tumors happen when glial cells, which support and protect nerve cells, begin to grow in an uncontrolled way along the optic nerves or nearby brain structures. this often happens without a clear trigger or identifiable cause.

Genetic factors may play a role in some people. Optic gliomas occur more often in people with neurofibromatosis type 1 (NF1), a genetic condition that affects how cells grow. NF1 increases the risk of developing an optic glioma, but it does not directly cause it.

In people without NF1, an optic glioma can happen without a known inherited cause and does not run in families. Researchers continue to study why these tumors form and what affects how they grow and what they do.

عوامل الخطورة

Certain factors are linked to a higher chance of developing an optic glioma, although many people who develop these tumors have no known risk factors.

The strongest known risk factor is neurofibromatosis type 1 (NF1). People with NF1 have a higher chance of developing optic gliomas, especially during childhood. Even so, many people with NF1 never develop optic glioma, and having NF1 does not mean optic glioma will definitely occur.

Age also is an important factor. Optic gliomas are most often diagnosed in children, especially in early childhood. These tumors are not common in adults, but when they occur later in life, they are more likely to be aggressive.

Optic glioma can still occur in people who do not have NF1 and do not have a family history of optic glioma. No environmental exposures or lifestyle factors have been clearly linked to getting optic glioma.

المضاعفات

Optic gliomas can lead to complications over time, particularly when they affect vision or nearby brain structures. The type of complications and how bad they are depend on the tumor's location and growth pattern and your age at diagnosis.

Vision-related complications may include:

• Lasting vision loss in one or both eyes.
• Worsening vision over time, even if the tumor grows slowly.
• Limited improvement in vision after treatment.

Hormone-related complications may occur when an optic glioma involves areas near the center of the brain that help regulate hormones. These complications may include:

• Early puberty.
• Growth pattern that is not typical.
• Hormone changes that can last even after the tumor stops growing.

Neurological or developmental complications may happen, especially in children or when nearby brain areas are affected. These complications may include:

• Learning challenges.
• Developmental delays.
• Trouble with balance or coordination.

Treatment-related complications also can occur and may include long-term effects related to surgery, radiation therapy or chemotherapy. These risks are considered carefully when deciding how and when to treat an optic glioma.

الوقاية

There is no known way to prevent optic gliomas. Most develop without a clear cause and are not linked to lifestyle or environmental factors.

Because optic gliomas cannot be prevented, care focuses on early detection and monitoring, especially for people at higher risk. This care may include:

• Regular eye exams to check vision changes.
• Imaging tests when symptoms or changes in vision appear.
• Ongoing monitoring for people with neurofibromatosis type 1 (NF1), even if there are no symptoms.

Early monitoring can help identify changes in vision or tumor growth sooner. This may allow for timely management and help reduce the risk of long-term complications.