Astrocytoma

Astrocytoma is a type of CNS tumor that forms in cells called astrocytes. Normal astrocytes provide the connecting network of the brain and spinal cord and form scar tissue when the CNS is damaged. Astrocytoma begins when normal astrocytes change and grow uncontrollably, forming a mass called a tumor.

Astrocytoma can occur throughout the CNS, including in the following places:

• Cerebellum (the back part of the brain responsible for coordination and balance)
• Cerebrum (the top part of the brain that controls motor activities and talking)
• Diencephalon or central part of the brain (controls vision, hormone production, and arm and leg movement)
• Brain stem (controls eye and facial movements, arm and leg movement, and breathing)
• Spinal cord (controls sensation and arm and leg motor function)

A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). Astrocytoma is more commonly referred to by its grade (a measure of how much the tumor cells appear like normal cells), as either high grade or low grade, depending 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  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.

Symptoms And Signs

Children with astrocytoma may experience the following symptoms or signs. Sometimes, children with astrocytoma do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not a tumor. If you are concerned about a symptom or sign on this list, please talk with your child’s doctor.

• Headaches
• Lethargy (feeling tired and listless)
• Seizures not related to a high fever
• Eyesight problems, such as double vision
• Changed growth or development

In a baby, the only symptom may be that the head is growing too fast. An infant’s skull can expand to make room for a growing tumor in the brain, so a baby with astrocytoma may have a larger than normal head.

Diagnosis

Doctors use many tests to diagnose a tumor and find out if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, a biopsy is the only way to make a definitive diagnosis. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the tumor has spread. This list describes options for diagnosing astrocytoma, and not all tests listed will be used for every person. Your child’s doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
• Type of tumor suspected
• Signs and symptoms
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose astrocytoma:

Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. A CT scan can also be used to measure the tumor’s size. Sometimes, a contrast medium (a special dye) is injected into a vein or given orally (by mouth) to provide better detail.

Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein or given orally to create a clearer picture.

Biopsy. Other tests can suggest that a tumor is present, but only a biopsy can make a definite diagnosis. For astrocytoma, a biopsy is done to determine the type and grade of the tumor. A neurosurgeon (a doctor who specializes in treating a CNS tumor using surgery) will remove a small piece of tissue from the tumor. The sample removed during the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).