A malignant brain tumor is a cancer of the brain. It's relatively common - slightly more so in men than in women - and may occur at any age. In adults, it most often strikes between ages 40 and 60. In children, the incidence of malignant brain tumors is generally highest before age 1 and then again between ages 2 and 12.
Malignant brain tumors are classified by the type of cancer cell. In adults, the most common tumors are gliomas and meningiomas. Usually, these tumors are located above the covering of the cerebellum - the area in the back of the brain that coordinates voluntary muscle movements.
What causes it?
The cause of a malignant brain tumor is unknown.
What are its symptoms?
A malignant brain tumor causes changes in the central nervous system (brain and spinal cord) by invading and destroying tissues and causing compression of the brain, cranial nerves, and cerebral blood vessels; brain swelling; and increased intracranial pressure (pressure within the skull). Increased intracranial pressure causes many of this cancer's symptoms, although they vary with the tumor type, its location, and the degree of invasion.
Because symptoms usually develop gradually, brain tumors are commonly misdiagnosed.
How is it diagnosed?
In many cases, a brain tumor is diagnosed by performing a tissue biopsy (removing and analyzing a small portion of brain tissue) during stereotactic surgery. In this procedure, a head ring is affixed to the person's skull, and a device that removes tissue is guided to the tumor by a computed tomography scan (commonly called a CAT scan) or magnetic resonance imaging (commonly known as MRI).
The doctor will also take the persons history and assess his or her neurologic status; the doctor also may order skull X-rays, a brain scan, a CAT scan, MRI, and cerebral angiography (a study of the blood vessels in the brain). A spinal tap shows increased pressure and protein levels, decreased sugar levels and, occasionally, tumor cells in cerebrospinal fluid.
How is it treated?
Treatment seeks to reduce the size of inoperable tumors, reduce brain swelling and increased intracranial pressure, prevent further neurologic damage, and relieve other symptoms. The treatment method depends on the type of tumor, its sensitivity to radiation, and its location.
If the tumor's location permits, surgery is performed to remove the tumor. If the tumor is inoperable, treatment may include some combination of radiation therapy, chemotherapy, and drug therapy.
