What are adult brain tumors?
What tests are used to find and diagnose adult brain tumors?
What is the grade of a tumor?

What are adult brain tumors?

Adult brain tumors are diseases in which cancer (malignant) cells begin to grow in the tissues of the brain. The brain controls memory and learning, senses (hearing, sight, smell, taste, and touch), and emotion. It also controls other parts of the body, including muscles, organs, and blood vessels.

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.

A doctor should be seen if the following symptoms appear:

• Frequent headaches.
• Vomiting.
• Loss of appetite.
• Changes in mood and personality.
• Changes in ability to think and learn.
• Seizures.

Tests that examine the brain and spinal cord are used to detect (find) adult brain tumor. The following tests and procedures may be used:

• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of the brain and spinal cord. A substance called gadolinium is injected into the patient through a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).

Adult brain tumor is diagnosed and removed in surgery. If a brain tumor is suspected, a biopsy is done by removing part of the skull and using a needle to remove a sample of the brain tissue. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are found, the doctor will remove as much tumor as safely possible during the same surgery. An MRI may then be done to determine if any cancer cells remain after surgery. Tests are also done to find out the grade of the tumor.

The grade of a tumor refers to how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. The pathologist determines the grade of the tumor using tissue removed for biopsy. The following grading system may be used for adult brain tumors:

Grade I

The tumor grows slowly, has cells that look similar to normal cells, and rarely spreads into nearby tissues. It may be possible to remove the entire tumor by surgery.

Grade II

The tumor grows slowly, but may spread into nearby tissue and may become a higher-grade tumor.

Grade III

The tumor grows quickly, is likely to spread into nearby tissue, and the tumor cells look very different from normal cells.

Grade IV

The tumor grows very aggressively, has cells that look very different from normal cells, and is difficult to treat successfully.

The chance of recovery (prognosis) and choice of treatment depend on the type, grade, and location of the tumor and whether cancer cells remain after surgery and/or have spread to other parts of the brain.

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