What is childhood visual pathway glioma?

What is childhood visual pathway glioma?

Childhood visual pathway glioma is a type of brain tumor in which cancer (malignant) cells begin to grow in the tissues of the brain. The brain controls memory and learning, the senses (hearing, sight, smell, taste, and touch), and emotion. It also controls other parts of the body, including muscles, organs, and blood vessels. Other than leukemia or lymphoma, brain tumors are the most common type of cancer that occurs in children.

Gliomas are a type of astrocytoma, tumors that start in brain cells called astrocytes. A visual pathway glioma occurs along the nerve that sends messages from the eye to the brain (the optic nerve). Visual pathway gliomas are visual pathway tumors. They may grow rapidly or slowly, depending on the grade of the tumor.

The risk of developing visual pathway gliomas is increased in children with a genetic disorder called neurofibromatosis type 1 (NF-1). NF-1 is a rare genetic condition that causes brown spots and tumors on the skin, freckling in skin areas not exposed to the sun, tumors on the nerves, and developmental changes in the nervous system, muscles, bone, and skin. Children with NF-1 who develop visual pathway gliomas may have a good chance of recovery and may not require treatment until symptoms appear or change.

This PDQ summary covers tumors that start in the brain (primary brain tumors). Often cancer found in the brain has started somewhere else in the body and has spread (metastasized) to the brain. This is called brain metastasis (refer to the PDQ summary on Adult Brain Tumors Treatment ¹ for more information).

Like most cancer, childhood brain tumor is best treated when it is found (diagnosed) early. If your child has symptoms, the doctor may order a computed tomographic (CT) scan, a special x-ray that uses a computer to make a picture of your child’s brain. A magnetic resonance imaging (MRI) scan, which uses magnetic waves to make a picture of your child’s brain, may also be done.

Often, surgery is required to see whether there is a brain tumor and to tell what type of tumor it is. The doctor may cut out a piece of tissue from the brain and look at it under a microscope. This is called a biopsy.

There are many types of brain tumors in children and the chance of recovery (prognosis) depends on the type of tumor, where it is located within the brain, and your child’s age and general health. See the PDQ summary on Childhood Brain and Spinal Cord Tumors Treatment Overview ² for more information about the types of childhood brain tumors.

Glossary Terms

A star-shaped cell that helps nerve cells in the brain and spinal cord work the way they should. An astrocyte is a type of glial cell.

A tumor that begins in the brain or spinal cord in small, star-shaped cells called astrocytes.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

Cancer that has spread from the original (primary) tumor to the brain.

The growth of abnormal cells in the tissues of the brain. Brain tumors can be benign (non-cancerous) or malignant (cancerous).

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

CT scan. A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called CT scan, computerized tomography, computerized axial tomography scan, and CAT scan.

The process of identifying a disease, such as cancer, from its signs and symptoms.

In medicine, a disturbance of normal functioning of the mind or body. Disorders may be caused by genetic factors, disease, or trauma.

Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

A cancer of the brain that begins in glial cells (cells that surround and support nerve cells).

The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. Magnetic resonance imaging makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. Magnetic resonance imaging is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called MRI, nuclear magnetic resonance imaging, and NMRI.

To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.

A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.

The organized network of nerve tissue in the body. It includes the central nervous system (the brain and spinal cord), the peripheral nervous system (nerves that extend from the spinal cord to the rest of the body), and other nerve tissue.

NF1. A rare genetic condition that causes brown spots and tumors on the skin, freckling in skin areas not exposed to the sun, tumors on the nerves, and developmental changes in the nervous system, muscles, bone, and skin. Also called NF1.

The nerve that carries messages from the retina to the brain.

A part of the body that performs a specific function. For example, the heart is an organ.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

The original tumor.

The likely outcome or course of a disease; the chance of recovery or recurrence.

To become well and healthy again.

A picture of structures inside the body. Scans often used in diagnosing, staging, and monitoring disease include liver scans, bone scans, and computed tomography (CT) or computerized axial tomography (CAT) scans and magnetic resonance imaging (MRI) scans. In liver scanning and bone scanning, radioactive substances that are injected into the bloodstream collect in these organs. A scanner that detects the radiation is used to create pictures. In CT scanning, an x-ray machine linked to a computer is used to produce detailed pictures of organs inside the body. MRI scans use a large magnet connected to a computer to create pictures of areas inside the body.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

A rare, slow-growing tumor that usually forms in the optic nerve, optic chiasm, or optic tract. These are parts of the nervous system that carry messages from the eye to the brain. Also called optic pathway glioma.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.