General Information About Childhood Central Nervous System Embryonal Tumors
Key Points for This Section
- Central nervous system embryonal tumors may begin in embryonic (fetal) cells that remain in the brain after birth.
- There are different types of CNS embryonal tumors.
- Pineoblastomas form in cells of the pineal gland.
- Certain genetic conditions increase the risk of childhood CNS embryonal tumors.
- Signs and symptoms of childhood CNS embryonal tumors or pineoblastomas depend on the child's age and where the tumor is.
- Tests that examine the brain and spinal cord are used to detect (find) childhood CNS embryonal tumors or pineoblastomas.
- A biopsy may be done to be sure of the diagnosis of CNS embryonal tumor or pineoblastoma.
- Certain factors affect prognosis (chance of recovery) and treatment options.
Central nervous system (CNS) embryonal tumors form in embryonic cells that remain in the brain after birth. CNS embryonal tumors tend to spread through the cerebrospinal fluid (CSF) to other parts of the brain and spinal cord.
The tumors may be malignant (cancer) or benign (not cancer). Most CNS embryonal tumors in children are malignant. Malignant brain tumors are likely to grow quickly and spread into other parts of the brain. When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Benign brain tumors grow and press on nearby areas of the brain. They rarely spread to other parts of the brain. Both benign and malignant brain tumors can cause symptoms and need treatment.
Although cancer is rare in children, brain tumors are the third most common type of childhood cancer, after leukemia and lymphoma. This summary is about 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. For information about the different types of brain and spinal cord tumors, see the PDQ summary on Childhood Brain and Spinal Cord Tumors Treatment Overview.
Brain tumors occur in both children and adults. Treatment for adults may be different from treatment for children. See the PDQ treatment summary on Adult Brain Tumors for more information on the treatment of adults.
The different types of CNS embryonal tumors include:
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. Medulloblastomas sometimes spread to the bone, bone marrow, lung, or other parts of the body, but this is rare.
- Central nervous system primitive neuroectodermal tumors
Central nervous system primitive neuroectodermal tumors (CNS PNETs) are fast-growing tumors that usually 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. CNS PNETs may also form in the brain stem or spinal cord.
There are four types of CNS PNETs:
- 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 ganglioneuroblastomas
CNS ganglioneuroblastomas are rare tumors that form in nerve tissue of the brain and spinal cord. They may form in one area and be fast growing or form in more than one area and be slow growing.
Medulloepitheliomas are fast-growing tumors that form in brain cells that line tubelike spaces in the brain and spinal cord.
- CNS neuroblastomas
Childhood CNS atypical teratoid/rhabdoid tumor is also a type of embryonal tumor, but it is treated differently than other childhood CNS embryonal tumors. See the PDQ summary on Childhood Central Nervous System Atypical Teratoid/Rhabdoid Tumor Treatment for more information.
Pineoblastomas form in cells of the pineal gland and are usually malignant. Pineoblastomas are 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 a lot like treatment for 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. Talk with your child’s doctor if you think your child may be at risk.
Risk factors for CNS embryonal tumors include having the following inherited diseases:
In most cases, the cause of CNS embryonal tumors is not known.
These and other signs and symptoms may be caused by childhood CNS embryonal tumors, pineoblastomas, or by other conditions. Check with your doctor if you have any of the following:
- Loss of balance, trouble walking, worsening handwriting, or slow speech.
- Lack of coordination.
- Double vision.
- Nausea and vomiting.
- General weakness or weakness on one side of the face.
- Unusual sleepiness or change in energy level.
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.
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.
- 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 MRI scan to look at the chemicals in brain tissue.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of the brain and spinal cord, 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.
- Lumbar puncture : A procedure used to collect cerebrospinal fluid (CSF) from the spinal column. This is done by placing a needle into the spinal column. A pathologist views the CSF under a microscope to look for cancer cells. This procedure is also called an LP or spinal tap.
If doctors think your child may have a CNS embryonal tumor or pineoblastoma, a biopsy may be done. 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 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.
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.
- 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).