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Friday, Jan 09, 2009 | 01:51 PM
Madisons Foundation - Moms And Dads In Search Of Needed Support
Optic Nerve Glioma
Sunday, 31 August 2003
Last Updated Tuesday, 13 January 2004
What
An optic nerve glioma is a tumor of the optic nerve, the pathway that carries visual information from the eye to the brain so that one can see. A glioma is a tumor made of glial cells, which are the cells that form the support structure for the optic nerve. Optic nerve gliomas involve a specific type of glial cell called astrocytes. Thus, an optic nerve glioma is often referred to as a low-grade astrocytoma; it is classified as a tumor that generally tends to grow slowly (low-grade). Optic nerve gliomas can affect different parts of the optic nerve. The tumor can grow along the portion that is closest to the eye. Alternatively, the glioma may be present behind this area at the chiasm, the place where the optic nerves from the right and left eye cross before sending visual information to the brain. The tumor can also affect the pathway behind the chiasm that leads directly to the brain. Gliomas generally do not spread to other parts of the body, and they represent only 2% of all brain tumors in children.Who
About 75% of optic nerve gliomas are seen in children under 10 years old. Children aged 2-6 years are most commonly affected. About 15 to 40% of children with the genetic disease Neurofibromatosis Type I (NF-1) have optic gliomas; conversely 10-40% of children with optic gliomas have NF-1.Signs and Symptoms
Signs and symptoms depend on where the glioma is located along the optic nerve. A glioma close to the eye tends to cause bulging of that eye and/or some vision loss. This type of glioma is usually not cancerous. If the glioma affects the optic chiasm, vision loss occurs in both of the eyes as the tumor prevents the optic nerve from carrying information between the eyes and the brain. Tumors between the chiasm and the brain may impair parts of the brain that release important hormones and thus can have serious consequences. malignant (cancerous) gliomas cause very rapid loss of vision and can spread, however, this type of glioma is fairly rare.Possible Causes
What causes the astrocytes of the glial cells to overgrow into a tumor is currently not known. It is currently an area of active research.Diagnosis
Because the glioma affects vision, a careful history of the child’s ability to see and use the eyes in finding objects and looking at them is warranted. A routine physical examination of the eye often does not reveal any abnormalities, unless it has begun to bulge forward. A referral to an ophthalmologist is often made for a more specialized examination. A special imagining procedure, a CT (computed tomography) scan is often used to detect the location of the tumor and to check for presence of fluid or swelling around the eye. An MRI (magnetic resonance image) provides more detail of the eye structures. These pictures of the eye will help explain what is causing the visual loss and help the doctor decide what type of treatment is necessary.Treatment
Treatment depends on the nature of the tumor. If the tumor is benign (noncancerous) and slow-growing, often no treatment is needed. MRIs should be done periodically to follow tumor growth. If it is likely that the tumor will continue to cause vision loss, radiation therapy or surgery may be recommended to remove the tumor. The effects of chemotherapy are still being researched and may be helpful, particularly if the tumor is aggressive or rapidly growing.Prognosis
The prognosis of children with optic gliomas is quite good, since most of these tumors have self-limited growth. If the tumor does grow and extend into other parts of the brain, the 10 year survival rate at present is only 40%. The worst prognosis is for children where the gliomas are found behind the chiasm where the increased pressure in the brain or interference with hormonal function has the potential to cause an earlier death. Each child’s future needs to be discussed with the child’s doctor.Connect with other parents
In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.Weblinks
National Cancer Institute
Excellent information about childhood optic nerve glioma, with links to ongoing clinical trials as well as to other useful websites and organizations.
Orphans of the Cancer Storm
This link provides information specifically about ONG as well as links to support and to other important weblinks.
Information Links to Brain Tumors
A nice website with a list of useful websites with information about optic nerve gliomas.