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General Information About Childhood Central Nervous System Embryonal Tumors
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Central nervous system embryonal tumors begin in embryonic (fetal) cells in the brain and spinal cord.
Central nervous system (CNS) embryonal tumors form in brain cells when the fetus is beginning to develop. The tumors may be benign (not cancer) or malignant (cancer). Most CNS embryonal tumors in children are malignant.
Although cancer is rare in children, brain tumors are the third most common type of childhood cancer, after leukemia and lymphoma.
This summary discusses the treatment of primary brain tumors (tumors that begin in the brain). The treatment of metastatic brain tumors, which begin in other parts of the body and spread to the brain, is not discussed in this summary.
Brain tumors can occur in both children and adults; however, treatment for children may be different than treatment for adults. See the PDQ treatment summary on Adult Brain Tumors for more information.
CNS embryonal tumors may form in different areas of the brain.
Childhood brain tumors are named based on the type of cell they formed in and where the tumor first formed in the brain. There are 6 different types of CNS embryonal tumors:
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Medulloblastoma
Medulloblastomas are fast-growing tumors that form in brain cells in the cerebellum. The cerebellum is at the lower back part of the brain between the cerebrum and the brain stem. The cerebellum controls movement, balance, and posture. Sometimes medulloblastoma spreads to the bone, bone marrow, lymph nodes, liver, or lung.
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Pineoblastoma
Pineoblastoma is a fast-growing tumor that forms in brain cells in or near the pineal gland. The pineal gland is a tiny organ in the brain that makes melatonin, a substance that helps control our sleep cycle.
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Pineal parenchymal tumors
Pineal parenchymal tumors form in pineocytes, a type of cell in the pineal gland. These tumors may be slow- or fast-growing.
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Supratentorial primitive neuroectodermal tumors
Supratentorial primitive neuroectodermal tumors are fast-growing tumors that form in brain cells in the cerebrum. The cerebrum is at the top of the head and is the largest part of the brain. The cerebrum controls thinking, learning, problem-solving, emotions, speech, reading, writing, and voluntary movement.
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Medulloepithelioma
Medulloepitheliomas are fast-growing tumors that form in brain cells that line tubelike spaces in the brain and spinal cord. These rare tumors are most common in infants and young children.
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Ependymoblastoma
Ependymoblastomas are fast-growing tumors that form in brain cells lining the fluid -filled spaces in the brain and spinal cord. These rare tumors are most common in infants and young children.
Certain genetic conditions increase the risk of childhood CNS embryonal tumors.
Anything that increases the risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Parents who think their child may be at risk should discuss this with the child's doctor. Risk factors for CNS embryonal tumors include having the following inherited diseases:
In most cases, the cause of CNS embryonal tumors is not known.
The symptoms of childhood CNS embryonal tumors are not the same in every child.
The following symptoms and others may be caused by a CNS embryonal tumor. Symptoms vary depending on the child's age and where the tumor is located. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
- Loss of balance, trouble walking, worsening handwriting, or slow speech.
- Morning headache or headache that goes away after vomiting.
- Nausea and vomiting.
- General weakness or weakness on one side of the face.
- Unusual sleepiness or change in energy level.
- Change in personality or behavior.
- Unexplained weight loss or weight gain.
An infant or young child may be irritable or grow slowly, and may not eat well or meet developmental milestones such as sitting, walking, and talking in sentences.
Tests that examine the brain and spinal cord are used to detect (find) childhood CNS embryonal tumors.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Neurological exam: A series of questions and tests to check the brain, spinal cord, and nerve function. The exam checks a patient's mental status, coordination, and ability to walk normally, and how well the muscles, senses, and reflexes work. This may also be called a neuro exam or a neurologic exam.
- 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) of the brain and spinal cord with gadolinium. A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the brain and spinal cord. A substance called gadolinium is injected into 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). Sometimes magnetic resonance spectroscopy (MRS) is
done during the same MRI scan to look at the chemical makeup of the brain tissue.
- Lumbar puncture: A procedure used to collect cerebrospinal fluid from the spinal column. This is done by placing a needle into the spinal column. This procedure is also called an LP or spinal tap.
- SPECT scan (single photon emission computed tomography): A procedure that uses a special camera linked to a computer to make a 3-dimensional (3-D) picture of the brain. A small amount of a radioactive substance is injected into a vein or inhaled through the nose. As the substance travels through the blood, the camera rotates around the head and takes pictures of the brain. There will be increased blood flow and more chemical reactions (metabolism) in areas where cancer cells are growing. These areas will show up brighter in the picture. This procedure may be done just before or after a CT scan.
- PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the brain. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
Childhood CNS embryonal tumors are usually diagnosed and removed in surgery.
If doctors think your child may have a CNS embryonal tumor, a biopsy may be done to remove a sample of tissue. For brain tumors, the biopsy is done by removing part of the skull and using a needle to remove a sample of tissue. Sometimes, a computer-guided needle is used to remove a sample of tissue. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are found, the doctor may remove as much tumor as safely possible during the same surgery.
The following tests may be done on the sample of tissue that is removed:
- Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancer.
- Light and electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.
- Cytogenetic analysis: A laboratory test in which cells in a sample of tissue are viewed under a microscope to look for certain changes in the chromosomes.
Some pineoblastoma and pineal parenchymal tumors are diagnosed by brain imaging tests.
Sometimes, it is not possible to do a safe biopsy or completely remove the tumor in surgery, because of where it is in the brain. These tumors are diagnosed based on the results of imaging tests and other procedures.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on:
- The age of the child when the tumor is found.
- The type of tumor and where it is in the brain.
- Whether there is tumor left after surgery.
- Whether the cancer has spread within the brain and spinal cord or to other parts of the body, such as the bones.
- Whether the tumor has just been diagnosed or has recurred (come back).
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