The brain and spinal column make up the central nervous system (CNS), where all vital functions of the body, including thought, speech, and strength, are controlled.
Astrocytoma is a type of CNS tumor that forms in cells called astrocytes. Healthy astrocytes provide the connecting network of the brain and spinal cord and form scar tissue when the CNS is damaged. Astrocytoma begins when healthy astrocytes change and grow uncontrollably, forming a mass called a tumor.
Astrocytoma can occur throughout the CNS, including in the following places:
- The cerebellum, which is the back part of the brain responsible for coordination and balance.
- The cerebrum, which is the top part of the brain that controls motor activities and talking
- The diencephalon or the central part of the brain that controls vision, hormone production, and arm and leg movement
- The brain stem, which controls eye and facial movement, arm and leg movement, and breathing
- The spinal cord, which controls sensation and arm and leg motor function
In general, a tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread. Astrocytoma is more commonly referred to as either high grade or low grade. Grade is a measure of how much the tumor cells appear like healthy cells and depends on the number and shape of the tumor cells and how quickly they grow and spread. A low-grade tumor is less likely to grow quickly or spread. Once a tumor is found in the CNS, the doctor will usually perform a biopsy (see Diagnosis) to see if the tumor is an astrocytoma and to determine the grade of the tumor. A biopsy is the removal of a small amount of tissue for examination under a microscope.
Normal brain tissueClick to Enlarge
Pilocytic astrocytomaClick to Enlarge
Anaplastic astrocytomaClick to Enlarge
These images used with permission by the College of American Pathologists.
This section covers astrocytoma diagnosed in children; learn more about brain tumors in adults.
Looking for More of an Overview?
If you would like additional introductory information, explore these related items. Please note these links will take you to other sections on Cancer.Net:
- ASCO Answers Fact Sheet: Read a one-page fact sheet (available as a PDF) that offers an easy-to-print introduction to CNS tumors.
- Cancer.Net Patient Education Videos: View short videos led by ASCO experts in childhood cancers and brain tumors that provide basic information and areas of research.
- Cancer.Net En Español: Read about astrocytoma in Spanish. Infórmase sobre astrocitoma en español.