Pediatric Brain Tumor Foundation
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About Brain Tumors in Childhood

How common are brain tumors in children?
What could have caused my child’s brain tumor?
What’s the difference between a benign and a malignant tumor?
So a benign brain tumor is not dangerous?
How do doctors determine the type of tumor and its level of aggressiveness?
Does the grade of tumor determine the outcome for my child?
What is medulloblastoma?
What are astrocytomas?
What is ependymoma?
What are some other types of brain and spinal cord tumors?
What’s the difference between a brain tumor recurrence and secondary cancer?


How common are brain tumors in children?
They are very rare. About 4,600 cases of tumor in the central nervous system (CNS), which is the brain and spinal cord, are diagnosed in children every year in the United States. That’s about 6 percent of all CNS tumors, which are significantly more common in older adults. In children, about three-quarters of cases are in those under 15.

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What could have caused my child’s brain tumor?
Nobody knows the cause of most brain tumors, although genetic disorders explain a minority of cases. Exposure to environmental toxins has been suspected, but has not been confirmed by research data. It is important to recognize that nothing you did as a parent led to your child’s diagnosis.

Note the distinction between primary CNS tumors, which start in the brain and/or spine, and secondary CNS tumors that spread to the CNS from other parts of the body. This information focuses on primary CNS tumors.

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What’s the difference between a benign and a malignant tumor?
CNS tumors are classified by pathologists as benign (non-malignant) or malignant based on the appearance of the cells under a microscope. Benign tumors are usually slow growing and do not spread from their original site; in some cases they have well-defined borders that make them easier to remove.

A malignant or cancerous brain tumor is always life threatening and is more challenging to treat. They typically grow rapidly, invading normal tissue. In some cases, cells from a malignant tumor break free from the mass and metastasize, or spread, to other parts of the CNS. (In rare cases, they spread to other parts of the body.)

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So a benign brain tumor is not dangerous?
Judging from its name, you would think so. But all CNS tumors (either benign or malignant) can be dangerous. For example, if a benign CNS tumor is located in a vital area of the brain or spinal cord, it can be life-threatening because the CNS controls breathing and swallowing, as well as movement, coordination, senses and behavior. Consequently some doctors refer to tumors as a non-malignant rather than benign. These non-malignant tumors can grow and become malignant. The specific type of your child’s tumor (for example, medulloblastoma) is much more informative than describing it as benign or malignant.

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How do doctors determine the type of tumor and its level of aggressiveness?
Most medical institutions identify tumor type and their grade, or level of aggressiveness, according to the classification system of the World Health Organization. A pathologist will determine type and grade after examining brain tissue under a microscope. Getting a second opinion can be useful, especially if the diagnosis is uncertain, because one pathologist’s assessment may not match another’s. Over time, both the type and grade of the tumor may change. Grades range from I (non-cancerous) to IV, the most aggressive.

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Does the grade of tumor determine the outcome for my child?
Not entirely. The grade provides information about the aggressiveness of that tumor type but does not indicate whether there are effective treatments for that tumor type. For example, most children with medulloblastoma, a grade IV tumor, survive. Additionally, a child with a grade III tumor that undergoes a gross total resection (GTR), or entire removal of the tumor, may fare better than one with a grade II tumor with a subtotal resection (STR). Age of diagnosis is another prognostic factor for some tumor types.

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What is medulloblastoma?
Medulloblastoma is the most common malignant brain tumor in children. Medulloblastomas typically originate in the cerebellum, the lower back part of the brain. They are grade IV tumors that grow quickly and may spread to other parts of the CNS.

Research has identified four subtypes of medulloblastoma; over time it is hoped that treatment will be tailored for each group to optimize effectiveness. Both radiation therapy and chemotherapy can be helpful to treat medulloblastoma.

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What are astrocytomas?
Astrocytomas are a type of glioma, a group of tumor which comes from the glial cells – the supportive tissue – of the brain. Astocytomas are a type of glioma arising from star-shaped brain cells called astrocytes and are the most common type of childhood brain tumor, representing one-third of diagnoses. They include grade I juvenile pilocytic astrocytoma (JPA),  grade II fibrillary astrocytoma, grade III anaplastic astrocytoma, as well as glioblastoma, a grade IV tumor that is significantly more common in adults but also affects some children.

Several other names are used for specific types of grade I to IV astrocytomas. These include optic gliomas, which are generally slow-growing tumors and often found in children with neurofibromatosis type I, an inherited disorder that can cause additional medical complications. Brainstem gliomas can also be malignant or non-malignant. Low-grade brainstem gliomas can be resected in some cases, but surgery is generally not used to treat diffuse intrinsic pontine gliomas (DIPG), an aggressive grade IV tumor that spreads widely throughout the brainstem.

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What is ependymoma?
An ependymoma is another type of glioma and the third most common type of childhood brain tumor. They comprise between 6 to 12 percent of childhood brain tumors and are usually located in the lining of the passageways in the brain or spinal cord.

Most children have grade II or grade III variants occurring in the brain. Grade III ependymoma, also known as anaplastic ependymoma, grows more rapidly and is more likely to spread to other parts of the brain and spine.

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What are some other types of brain and spinal cord tumors?
Tumors can develop when cells in the embryo that migrate to the developing gonads mistakenly travel to the brain. These tumors are called CNS germ cell tumors and include choriocarcinoma, embryonal carcinoma, germinoma, mixed germ cell tumors, teratoma and yolk sac tumors. They account for about 3 percent of childhood brain tumors and can be non-malignant or malignant.

Other types of tumors include choroid plexus papilloma, craniopharyngioma, vestibular schwannoma, mixed neuronal-glial tumors (including gangliogliomas), meningioma and pituitary adenoma. These tumors are generally non-malignant. However, some can be malignant or may become malignant over time.

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What’s the difference between a brain tumor recurrence and secondary cancer?
Recurrence means that your child’s original tumor has returned. This can occur weeks, months or up to five years following the original diagnosis. In rare cases it can happen much later.

Secondary cancers are new cancers caused by treatment and usually develop at least five years after treatment of the original tumor. This is much less common than recurrence of the original tumor. For example, chemotherapy can cause the blood cancer acute myelogenous leukemia (AML) around five to nine years after treatment.

In addition, children who have undergone radiation are at risk for secondary brain tumors, which can be malignant or non-malignant. These tumors usually occur at least 10 years after radiation. It’s important to recognize that the danger of developing a secondary cancer, while not insignificant, is small compared to the danger of not undergoing treatment.

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