Gliomas

• The most common brain tumors are gliomas, which arise from the glial (supportive) tissue.

Types of Gliomas:

Astrocytomas arise from small, star-shaped cells called astrocytes. They may grow anywhere in the brain or spinal cord. In adults, astrocytomas most often arise in the cerebrum. In children, they occur in the brain stem, the cerebrum, and the cerebellum. A grade III astrocytoma is sometimes called anaplastic astrocytoma. A grade IV astrocytoma is usually called glioblastoma multiforme.

Brain stem gliomas occur in the lowest, stemlike part of the brain. The brain stem controls many vital functions. Tumors in this area generally cannot be removed. Most brain stem gliomas are high-grade astrocytomas.

Ependymomas usually develop in the lining of the ventricles. They also may occur in the spinal cord. Although these tumors can develop at any age, they are most common in childhood and adolescence.

Oligodendrogliomas arise in the cells that produce myelin, the fatty covering that protects nerves. These tumors usually arise in the cerebrum. They grow slowly and usually do not spread into surrounding brain tissue. Oligodendrogliomas are rare. They occur most often in middle- aged adults but have been found in people of all ages.