Optic glioma Health Article

Definition

Gliomas are tumors that grow in various parts of the brain. Optic gliomas can affect:

• One or both of the optic nerves, which carry visual information to the brain from each eye
• The optic chiasm, the area where the optic nerves cross each other in front of the hypothalamus of the brain

An optic glioma may also grow along with a hypothalamic glioma.

Alternative Names

Glioma - optic; Optic nerve glioma

Causes, incidence, and risk factors

Optic gliomas are rare. The cause of optic gliomas is unknown. Most optic gliomas are slow-growing and non-cancerous (benign) and occur in children, almost always before age 20.

There is a strong association between optic glioma and neurofibromatosis Type 1 (NF1).

Symptoms

The symptoms are due to the tumor growing and pressing on the optic nerve and nearby structures. Symptoms may include:

• Squinting
• Vision loss in one or both eyes
  • May be a loss of peripheral vision or vision loss may be more general
  • Leads to eventual blindness
• Involuntary eyeball movement
• One or both eyes may bulge outward

The patient may show symptoms of Diencephalic syndrome, which includes delayed growth, loss of appetite and body fat, daytime sleeping and decreased memory and intellectual function.

Signs and tests

A neurologic examination reveals a loss of vision in one or both eyes. There may be changes in the optic nerve, including swelling or scarring of the nerve, or paleness and atrophy of the optic disk.

The tumor may extend into deeper locations of the brain. There may be signs of increased pressure within the brain (intracranial pressure). There may be signs of NF1.

The following tests may be performed:

• Head CT scan or MRI of the head -- confirms the diagnosis and the exact location of the tumor
• Cerebral angiography -- often not necessary, but if used, it shows a space-occupying mass
• Visual field tests -- can help determine how invasive the tumor is
• Tissue removed from the tumor during surgery or CT scan-guided biopsy -- examined to confirm the exact type of tumor.