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 signs or 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 summary on Adult Central Nervous System Tumors Treatment 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.
CNS 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 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 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.
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.
Pineoblastoma is linked with inherited changes in the retinoblastoma (RB1) gene. A child with the inherited form of retinoblastoma (cancer than 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.
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 other conditions. Check with your child's doctor if your child has any of the following:
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:
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 test may be done on the sample of tissue that is removed:
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