Brain tumor

What is a pediatric brain tumor?

A pediatric brain tumor is a growth of abnormal cells in a child's brain. About 3,000 children in the United States are diagnosed with brain tumors each year, most between the ages of 3 and 12. There are many types of pediatric brain tumors, distinguished by where in the brain they develop and whether they are malignant (cancerous) or benign (noncancerous). Cancerous brain tumors are the second most common cancer in children, after leukemia.

Brain tumors in children are different from brain tumors in adults and generally more responsive to treatment. If your child is diagnosed with a brain tumor, the outlook depends on certain factors, such as their age, the type of tumor, its location and how much can be surgically removed.

Causes of pediatric brain tumors

Most brain tumors in children result from genetic abnormalities in the cells that become a tumor. Researchers are studying parents of children with brain tumors to see whether exposure to certain chemicals may alter a gene that protects the body from cancer. In addition, children who have undergone radiation therapy to the head for other cancers are at a higher risk for developing brain tumors.

Benign brain tumors don't contain cancer cells. If completely removed by surgery, they usually won't return. If they can't be fully removed, the remaining tumor may grow, which could require additional treatments, such as chemotherapy or radiation. Malignant brain tumors require immediate treatment. They usually grow quickly, spread to surrounding tissue and may return after treatment.

Types of pediatric brain tumors

There are two main categories of brain tumors, primary and secondary.

Primary brain tumors

Tumors that begin in brain tissue are known as primary brain tumors. The most common are gliomas, which begin in the brain's glial cells (tissue that supports the nerve cells). Types of gliomas include:

• Astrocytomas. These brain tumors originate from star-shaped brain cells called astrocytes. Two of the more common types are high-grade astrocytomas and cerebellar low-grade astrocytomas.
• Brainstem gliomas. These tumors develop in the brain stem, which controls vital functions, such as breathing, heartbeat and blood pressure.
• Ependymomas. These tumors form in ventricles (fluid-filled spaces) in the brain and spinal cord.

Types of primary brain tumors that don't begin in glial tissue include:

• Choroid plexus tumors. These form in tissues of the choroid plexus, which produces cerebrospinal fluid in the brain.
• Craniopharyngiomas. These tumors grow near the base of the brain. They can affect the pituitary gland (which makes some hormones and controls overall hormonal function), the optic nerve and other nearby structures.
• Germ cell tumors. These develop in cells that become eggs or sperm. Germ cell tumors may occur anywhere in the body as well as in the ovaries and testes.
• Medulloblastomas. These develop in the cerebellum, a part of the brain located at the lower back of the head that's involved in balance and coordination.
• Pineal region tumors. These begin in the brain's pineal gland, which produces melatonin, the hormone that regulates sleep-wake cycles.

Secondary brain tumors

A secondary brain tumor occurs when cancer begins in another body part and spreads to the brain. For example, if lung cancer travels to the brain, it is a secondary brain tumor caused by metastatic lung cancer. In this case, the tumor cells resemble abnormal lung cells, not abnormal brain cells. Secondary brain tumors are rare in children, accounting for fewer than 5% of cases.

Symptoms of pediatric brain tumors

Common signs of brain tumors in children may include:

• Headaches (often worse in the morning)
• Nausea and vomiting
• Seizures
• Irritability and personality changes
• Vision problems, including blurred vision and irregular eye movements
• Fatigue

Diagnosis of pediatric brain tumors

If your child's doctor suspects a brain tumor, the first step will be a physical exam, checking for certain signs, such as swelling behind the eyes. Typically, the doctor will recommend a CT scan or MRI scan to obtain detailed images of the brain.

Blood tests are performed to check whether your child can safely undergo diagnostic surgery, if needed, such as a biopsy to identify the tumor type. The biopsy may require more than one operation, depending on the tumor's characteristics and your child's overall health.

Treatment of pediatric brain tumors

UCSF neurologists and neurosurgeons are supported by one of the most advanced imaging centers in the world, with access to guidance from pioneers in the field. We use MRI scanning during operations to increase surgical accuracy and are one of only a few centers in California offering noninvasive treatments with the Gamma Knife and CyberKnife.

We are also leaders in research on new treatments. Our patients often have opportunities to participate in clinical trials investigating promising medications and procedures. And our research laboratories are studying the molecular abnormalities that give rise to pediatric brain tumors.