General Information About Childhood Medulloblastoma and Other Central Nervous System Embryonal Tumors
Medulloblastoma and other central nervous system (CNS) embryonal tumors may begin in embryonic (fetal) cells that remain in the brain after birth.
Medulloblastoma is a fast-growing tumor that forms in the cerebellum (the lower, back part of the brain). Medulloblastoma is the most common type of CNS embryonal tumor. CNS embryonal tumors are uncontrolled growths of cells in the brain. These tumors form in cells that are left over from fetal development, called embryonal cells. Pineoblastoma is a fast-growing type of brain tumor that forms in or around a tiny organ near the center of the brain called the pineal gland.
These tumors may be benign (not cancer) or malignant (cancer). Benign brain tumors grow and press on nearby areas of the brain but rarely spread to other parts of the brain. Malignant brain tumors are likely to grow quickly and spread into other parts of the brain. They may also spread to other parts of the body, but this is rare. When a tumor grows into and presses on an area of the brain or spreads to other parts of the brain, it may stop that part of the brain from working the way it should. Both benign and malignant brain tumors can cause serious signs or symptoms and need treatment.
Most medulloblastomas, other CNS embryonal tumors, and pineoblastomas in children are malignant. These tumors tend to spread through the cerebrospinal fluid to other parts of the brain and spinal cord.
Although cancer is rare in children, brain tumors are the second most common type of childhood cancer, after leukemia. This summary is about the treatment of primary brain tumors (tumors that begin in the brain).
Anatomy of the inside of the brain, showing the pineal and pituitary glands, optic nerve, ventricles (with cerebrospinal fluid shown in blue), and other parts of the brain.
There are different types of CNS embryonal tumors.
The different types of CNS embryonal tumors include:
Medulloblastomas
Most CNS embryonal tumors are medulloblastomas. 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. It is rare for medulloblastomas to spread to the bone, bone marrow, lung, or other parts of the body.
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Other types of CNS embryonal tumors (nonmedulloblastoma)
Other types of CNS embryonal tumors are fast-growing tumors and may form in brain cells anywhere in the brain, including the cerebrum, brain stem, or spinal cord. 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. It is rare for these tumors to spread to the bone, bone marrow, lung, or other parts of the body.
There are many types of CNS embryonal (nonmedulloblastoma) tumors:
- Cribriform neuroepithelial tumors
Cribriform neuroepithelial tumor forms in the ventricles in the brain. This tumor most often occurs in infants and young children. Cribriform neuroepithelial tumor occurs more often in boys.
- Embryonal tumors with multilayered rosettes
Embryonal tumors with multilayered rosettes (ETMR) are rare tumors that form in the brain and spinal cord. ETMR most commonly occur in young children and are fast-growing tumors.
- CNS neuroblastomas
CNS neuroblastomas are a very rare type of neuroblastoma that form in the nerve tissue of the cerebrum or the layers of tissue that cover the brain and spinal cord. CNS neuroblastomas may be large and spread to other parts of the brain or spinal cord.
- CNS high-grade neuroepithelial tumor with a change in the BCOR gene
CNS high-grade neuroepithelial tumor is a very rare tumor that forms in the brain. This tumor occurs most often in children younger than 10 years, but can occur in older children and adolescents.
- CNS Ewing sarcoma with a change in the CIC gene
CNS Ewing sarcoma is a very rare tumor found in the brain or spine. This tumor most often occurs in children younger than 10 years.
- CNS high-grade neuroepithelial tumor with a change in the MN1 gene
CNS high-grade neuroepithelial tumor is a very rare tumor that forms in the brain or spinal cord. This tumor most often occurs in adolescents and females.
- Medulloepitheliomas
Medulloepithelioma is a fast-growing tumor that usually forms in the brain, spinal cord, or nerves just outside the spinal column. It occurs most often in infants and young children.
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CNS atypical teratoid/rhabdoid tumor is also a type of embryonal tumor, but it is treated differently than other childhood CNS embryonal tumors. For more information, see Childhood Central Nervous System Atypical Teratoid/Rhabdoid Tumor Treatment.
Pineoblastoma forms in cells of the pineal gland.
The pineal gland is a tiny organ in the center of the brain. The gland makes melatonin, a substance that helps control our sleep cycle. Pineoblastoma are usually malignant fast-growing tumors with cells that look very different from normal pineal gland cells. Pineoblastomas are not a type of CNS embryonal tumor but treatment for them is similar to treatment for CNS embryonal tumors.
Pineoblastoma is linked with inherited changes in the retinoblastoma (RB1) gene. A child with the inherited form of retinoblastoma (cancer that forms in the tissues of the retina) has an increased risk of pineoblastoma. When retinoblastoma forms at the same time as a tumor in or near the pineal gland, it is called trilateral retinoblastoma. MRI (magnetic resonance imaging) testing in children with retinoblastoma may detect pineoblastoma at an early stage when it can be treated successfully. It is rare for pineoblastoma to spread to the bone, bone marrow, lung, or other parts of the body.
Certain genetic conditions increase the risk of childhood medulloblastoma.
Childhood medulloblastoma is caused by certain changes to the way brain cells function, especially how they grow and divide into new cells. Often, the exact cause of the cell changes is unknown. To learn more about how cancer develops, see What is Cancer?.
A risk factor is anything that increases the chance of getting a disease. Not every child with one or more of these risk factors will develop medulloblastoma, and it will develop in some children who don't have a known risk factor. Talk with your child's doctor if you think your child may be at risk.
The risk for medulloblastoma is increased in people who have any of the following inherited diseases:
- Turcot syndrome
- Rubinstein-Taybi syndrome
- Nevoid basal cell carcinoma (Gorlin) syndrome
- Li-Fraumeni syndrome
- Fanconi anemia
Genetic counseling may be done for children with medulloblastoma or pineoblastoma.
It may not be clear from the family medical history whether a child with a brain tumor has an inherited condition that increased their risk. Genetic counselors and other specially trained health professionals can discuss your child's diagnosis and the family's medical history to understand:
- your options for ELP1, APC, SUFU, PTCH1, TP53, PALB2, or BRCA2 gene testing if your child has medulloblastoma
- your options for RB1 or DICER1 gene testing if your child has pineoblastoma
- the risk of other cancers for your child
- the risk of cancer for your child's siblings
- the risks and benefits of learning genetic information
Genetic counselors can also help you cope with your child's genetic testing results, including how to discuss the results with family members.
Symptoms of medulloblastoma, other CNS embryonal tumors, and pineoblastoma depend on the child's age and where the tumor is.
Children may not have symptoms of medulloblastoma, other CNS embryonal tumors, or pineoblastoma until the tumor has grown bigger. It's important to check with your child's doctor if your child has any symptoms below:
- loss of balance, trouble walking, lack of coordination, or slow speech
- headache, especially in the morning, or headache that goes away after vomiting
- general weakness
- weakness on one side of the face
- unusual sleepiness or change in energy level
- seizures
- double vision or other eye problems
- nausea and vomiting
Infants and young children with these tumors may be irritable or grow slowly. Also they may not eat well or meet developmental milestones such as sitting, walking, and talking in sentences. These tumors may also cause an increase in the size of an infant's head.
These symptoms may be caused by conditions other than medulloblastoma, other CNS embryonal tumors, or pineoblastoma. The only way to know is to see your child's doctor. The doctor will ask you when the symptoms started and how often your child has been having them as a first step in making the diagnosis.
Tests that examine the brain and spinal cord are used to diagnose childhood medulloblastoma, other CNS embryonal tumors, and pineoblastoma.
If your child has symptoms that suggest medulloblastoma, another type of CNS embryonal tumor, or pineoblastoma, the doctor will need to find out if these are due to cancer or another condition. They will ask about your child's personal and family health history and do a physical exam. Depending on the results, the doctor may recommend tests to find out if your child has a brain tumor. The results of these tests will also help you and your child's doctor plan treatment.
The following tests and procedures are used to diagnose medulloblastoma, other CNS embryonal tumors, and pineoblastoma:
- MRI (magnetic resonance imaging) of the brain and spinal cord with gadolinium is 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 MRI scan to look at the chemicals in brain tissue.
- CT scan (CAT scan) uses a computer linked to an x-ray machine to make a series of detailed pictures inside the body from different angles. 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. To learn more, see Computed Tomography (CT) Scans and Cancer.
- Lumbar puncture is a procedure used to collect cerebrospinal fluid (CSF) from the spinal column. This is done by placing a needle between two bones in the spine and into the CSF around the spinal cord and removing a sample of the fluid. The sample of CSF is checked under a microscope for signs of tumor cells. The sample may also be checked for the amounts of protein and glucose. A higher-than-normal amount of protein or lower-than-normal amount of glucose may be a sign of a tumor. This procedure is also called an LP or spinal tap.
Lumbar puncture. A patient lies in a curled position on a table. After a small area on the lower back is numbed, a spinal needle (a long, thin needle) is inserted into the lower part of the spinal column to remove cerebrospinal fluid (CSF, shown in blue). The fluid may be sent to a laboratory for testing.
A biopsy may be done to be sure of the diagnosis.
If doctors think your child may have medulloblastoma, another type of CNS embryonal tumor, or pineoblastoma, a biopsy may be done. 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 the tissue sample. 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 piece of skull is usually put back in place after the procedure.
Craniotomy. An opening is made in the skull and a piece of the skull is removed to show part of the brain.
The following test may be done on the sample of tissue that is removed:
- Immunohistochemistry is a laboratory test that uses antibodies to check for certain antigens (markers) in a sample of a patient's tissue. The antibodies are usually linked to an enzyme or a fluorescent dye. After the antibodies bind to a specific antigen in the tissue sample, the enzyme or dye is activated, and the antigen can then be seen under a microscope. This type of test is used to help diagnose cancer and to help tell one type of cancer from another type of cancer.
Certain factors affect prognosis (chance of recovery) and treatment options.
If your child has been diagnosed with medulloblastoma, other CNS embryonal tumor, or pineoblastoma, you may have questions about how serious the cancer is and your child's chances of survival. The likely outcome or course of a disease is called prognosis.
The prognosis and treatment options depend on:
- the type of tumor and where it is in the brain
- whether the cancer has spread within the brain and spinal cord when the tumor is found
- the age of the child when the tumor is found
- how much of the tumor remains after surgery
- whether there are certain changes in the chromosomes, genes, or brain cells
- whether the tumor has just been diagnosed or has recurred (come back)
Your child's cancer care team is in the best position to talk with you about your child's prognosis.
You may want to get a second opinion.
You may want to get a second opinion to confirm your child's diagnosis and treatment plan. If you seek a second opinion, you will need to get important medical test results and reports from the first doctor to share with the second doctor. The second doctor will review the pathology report, slides, and scans before giving a recommendation. The doctor who gives the second opinion may agree with the first doctor, suggest changes or another approach, or provide more information about your child's tumor.
To learn more about choosing a doctor and getting a second opinion, see Finding Cancer Care. You can contact NCI's Cancer Information Service via chat, email, or phone (both in English and Spanish) for help finding a doctor or hospital that can provide a second opinion. For questions you might want to ask at your appointments, see Questions to Ask Your Doctor About Cancer.