General Information About Childhood Central Nervous System Atypical Teratoid / Rhabdoid Tumor
Central nervous system (CNS) atypical teratoid/rhabdoid tumor (AT/RT) is a cancer that forms in the tissues of the brain.
Central nervous system (CNS) atypical teratoid/rhabdoid tumor (AT/RT) is a very rare, fast-growing cancer that begins in the brain and spinal cord. It usually occurs in children aged 3 years and younger, although it can occur in older children and adults.
About half of these tumors form in the cerebellum or brain stem. The cerebellum is the part of the brain that controls movement, balance, and posture. The brain stem controls breathing, heart rate, and the nerves and muscles used in seeing, hearing, walking, talking, and eating. AT/RT can also begin in other parts of the brain and spinal cord.
Anatomy of the brain. The supratentorial area (the upper part of the brain) contains the cerebrum, lateral ventricle and third ventricle (with cerebrospinal fluid shown in blue), choroid plexus, pineal gland, hypothalamus, pituitary gland, and optic nerve. The posterior fossa/infratentorial area (the lower back part of the brain) contains the cerebellum, tectum, fourth ventricle, and brain stem (midbrain, pons, and medulla). The skull and meninges protect the brain and spinal cord.
Certain genetic changes may increase the risk of AT/RT.
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 AT/RT. And it will develop in some children who don't have a known risk factor.
AT/RT may be linked to changes in the tumor suppressor genes SMARCB1 or SMARCA4. Tumor suppressor genes make a protein that helps control how and when cells grow. Changes in the DNA of tumor suppressor genes like SMARCB1 or SMARCA4 may lead to cancer.
The changes in the SMARCB1 or SMARCA4 genes may be inherited (passed on from parents to offspring). When this gene change is inherited, tumors may form in two parts of the body at the same time (for example, in the brain and the kidney). For children with AT/RT, genetic counseling (a discussion with a trained professional about inherited diseases and a possible need for gene testing) may be recommended.
Talk with your child's doctor if you think your child may be at risk.
The symptoms of AT/RT are not the same in every person.
Symptoms depend on:
- the child's age
- where the tumor has formed
Because AT/RT is fast growing, symptoms may develop quickly and get worse over a period of days or weeks. It's important to check with your child's doctor if your child has:
- a morning headache or headache that goes away after vomiting
- nausea and vomiting
- unusual sleepiness or change in activity level
- loss of balance, lack of coordination, or trouble walking
- an increase in head size (in infants)
- pain, tingling, numbness, or paralysis in the face
These symptoms may be caused by problems other than AT/RT. The only way to know is to see your child's doctor.
CNS AT/RT is found with tests that examine the brain and spinal cord.
If your child has symptoms that suggest AT/RT, the doctor will need to find out if these are due to cancer or another problem. The doctor will ask when the symptoms started and how often your child has been having them. They will also ask about your child's personal and family health history and do a physical exam, including a neurological exam. Depending on these results, they may recommend other tests. If your child is diagnosed with AT/RT, the results of these tests will help you and your child's doctor plan treatment.
The tests used to diagnose AT/RT may include:
- Magnetic resonance imaging (MRI) uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the brain and spinal cord. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- 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 lining around the spinal cord to remove a sample of the CSF. 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. This procedure is also called an LP or spinal tap.
- SMARCB1 and SMARCA4 gene testing is a laboratory test in which a sample of blood or tissue is tested for certain changes in the SMARCB1 and SMARCA4 genes. Children with AT/RT may be eligible for gene testing through the Molecular Characterization Initiative.
The Molecular Characterization Initiative offers free molecular testing to children, adolescents, and young adults with certain types of newly diagnosed cancer. The program is offered through NCI's Childhood Cancer Data Initiative. To learn more, visit About the Molecular Characterization Initiative.
- Ultrasound exam uses high-energy sound waves (ultrasound) that bounce off internal tissues or organs, such as the kidney, and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is done to check for tumors that may also have formed in the kidney.
Childhood AT/RT is diagnosed using a biopsy, and the tumor may be removed in the same surgery.
If doctors think there might be a brain tumor, a biopsy may be done to remove a sample of tissue. For brain tumors, the biopsy can be done by removing part of the skull or making a small hole in the skull and using a needle or surgical device to remove a sample of tissue. Sometimes, when a needle is used, it is guided by a computer 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 pathologist checks the cancer cells to find out the type of brain tumor. It is often difficult to completely remove AT/RT because of where the tumor is in the brain and because it may already have spread at the time of diagnosis. 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 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 AT/RT, you likely 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 depends on:
- whether your child has certain inherited gene changes
- whether the tumor has certain gene changes
- your child's age
- the amount of tumor remaining after surgery
- whether the cancer has spread to other parts of the brain and spinal cord or to the kidney at the time of diagnosis
- whether the cancer has just been diagnosed or has recurred (come back)
No two people are alike, and responses to treatment can vary greatly. Your child's cancer care team is in the best position to talk with you about your child's prognosis.