Brain tumor is an abnormal, excessive growth of tissue in the brain . Because the brain is an important and delicate organ, brain tumors can endanger a person’s life. Tumors that originate in the brain are called primary brain tumors. Other tumors may begin elsewhere in the body and spread to the brain in a process called metastasis << muh TAS tuh sihs >> . This article deals with primary brain tumors. For more information on metastasis, see Cancer .
Symptoms and diagnosis.
Symptoms of a brain tumor can include headache , seizures, loss of vision, and loss of memory . The diagnosis of brain tumor requires a full examination by a neurologist , a doctor who specializes in treating diseases of the nervous system . Neurologists often use a scanning technique called magnetic resonance imaging (MRI) to diagnose brain tumors in patients.
Cause.
Medical researchers do not know the exact cause of primary brain tumors. Scientists have found that people with a parent or sibling with a brain tumor have a doubled risk of developing one themselves. This evidence indicates that the development of brain tumors has a genetic (hereditary) component. However, brain tumors do not typically run in families.
Scientists have identified certain mutations in the cells that make up some brain tumors. A mutation is a change in the genes of a cell. Genes guide the way a cell develops and functions. Such mutations may cause the cells to multiply out of control. The evidence suggests that brain tumors may develop as a result of mutations in genes involved in brain cell metabolism or in the maintenance of structures called telomeres. Metabolism is the sum of chemical processes by which cells produce the energy and materials they need. Telomeres are a protective structure at the ends of chromosomes. Chromosomes are the threadlike structures in cells that carry genetic material.
Types of brain tumors.
Primary brain tumors are classified as either benign or malignant. Benign brain tumors tend to grow relatively slowly and to remain confined to one location. Malignant brain tumors tend to grow more quickly and spread within the brain or spinal cord. A malignant brain tumor is also called brain cancer. Both benign and malignant brain tumors can be life threatening.
The most common brain tumor in adults is called meningioma. This tumor is usually benign and occurs in the membranes covering the brain. The next most common tumor is glioma << gly OH muh >> , a malignant tumor made up of brain cells called glia. Glia normally serve as support cells for the billions of nerve cells, called neurons, in the brain. Glioma varieties include astrocytoma, oligodendroglioma, and ependymoma. They are named for the kind of glia cells from which they develop. Glioblastoma is the most common and most deadly kind of adult glioma. This kind of tumor tends to be aggressive—that is, it grows and spreads rapidly. Other gliomas are usually less aggressive than glioblastoma. Ependymoma is often malignant in children, but it is usually benign when it occurs in adults.
Treatment.
Surgical removal of the tumor usually cures meningioma. Treatment of glioblastoma involves surgical removal of the tumor along with radiation and chemotherapy (treatment with strong drugs). Even with treatment, most patients with glioblastoma die within two years of diagnosis.
Adults with astrocytoma or oligodendroglioma undergo surgery to remove the tumor and may also receive radiation or chemotherapy. These tumors are initially less aggressive than glioblastoma. However, they often continue to grow slowly and are eventually fatal.
In children.
Brain tumors in children usually differ from those found in adults. In children younger than 15 years of age, the most common types of brain tumors are malignant glioma, benign pilocytic astrocytoma, medulloblastoma, and ependymoma. Brain tumors in children are also classified by their location. For example, diffuse intrinsic pontine glioma (DIPG) is a glioma found in the pons of the brainstem. This part of the brain controls breathing and other bodily functions.
Removal of the tumor frequently cures child patients with some forms of astrocytoma. Malignant glioma and medulloblastoma may require additional treatment, including radiation and chemotherapy. Because of its location in the brainstem, DIPG cannot be surgically removed and is fatal.
