ATRT (atypical teratoid/rhabdoid tumor)

A rare, fast-growing brain and spine tumor, usually in very young children. Written for a parent. What the name means, and the signs that mean going in now. Why treatment is planned around your child's age. And what the months ahead actually involve.

The short version

This page is for a parent. ATRT is a rare, fast-growing cancer that starts in the brain or the spine. It usually happens in very young children, most often before age 3.

The full name is atypical teratoid/rhabdoid tumor. You may see it written ATRT or AT/RT. They are the same tumor.

Treatment usually has three parts: an operation, then strong chemotherapy, and then radiation for some children. Your child's age changes the plan, especially the radiation part of it.

Some signs mean calling your team today. A few mean going in now. They are in their own section below.

What is ATRT?

It is a cancer. Your team may use the word malignant. It grows quickly, and it can spread through the fluid that moves around the brain and the spine.

Most children with this tumor are babies or toddlers. Half are diagnosed at about 1 year old or younger. About two in three are found before age 2. Older children get it, and so do adults, but that is rare.

About half of these tumors begin in the lower rear of the brain, the cerebellum or the brain stem. Others begin higher up. A small number begin in the spinal cord itself.

It is an embryonal tumor. That is a group of tumors that medulloblastoma also belongs to. The rules that name brain tumors put them in separate groups inside it.

Is it cancer? What does its grade mean?

Yes, it is cancer, and doctors grade it 4. That is the highest step on the scale.

Grade describes how the cells look, not how long anyone will live. Under a microscope, a pathologist compares tumor cells with normal ones. Cells that look close to normal are a low grade. Cells that look very different are a high grade. Higher grades may grow and spread more quickly.

Every tumor in this group is grade 4. The rules that name brain tumors put all embryonal tumors at grade 4 together, rather than giving this one its own number. So the grade tells you the family your child's tumor belongs to. It does not sort one child's tumor from another's.

Grades are now written as ordinary numbers, so grade 4 rather than grade IV. If an older letter uses Roman numerals, it means the same thing.

What matters more than the number is where the tumor is, whether it has spread, and what your team can do about it. Those are the next sections.

Where does it grow, and why does it cause these symptoms?

Start with the fluid. The brain is bathed in a watery fluid. It circles the brain, runs down around the cord, and drains off. A growth in the wrong spot can dam that route. Fluid then pools behind the blockage, and pressure inside the head climbs. Doctors call that hydrocephalus.

And here is the part that works differently in a baby. In an adult the skull is locked shut, so rising pressure has nowhere to go. In a baby the skull can still give. The bony plates have not knitted together yet, and there is a gap near the crown, under the skin, where they have yet to meet. So the head itself can enlarge, and that gap can push outward.

That makes the early warning harder to read, in two ways.

• It changes the warning. The pressure can show up in the head itself, not only in the headaches an older child could describe.
• It disguises things. The early signs are the ordinary ones on the list below: unsettled, feeding poorly, sleeping more.

This is why a head that is growing too fast is taken seriously. It is not a small finding.

The tumor can travel in that fluid too. Loose cells drift with the current and can take hold somewhere else, higher up or lower down the cord. That is why your team images the whole spine and samples the fluid, and it is part of why treatment often has to reach the entire nervous system instead of one spot.

That is a lot to take in, and none of it is yours to work out. Your team does the finding. What this section is for is making the words they use make sense when they use them.

And if you want the place itself explained. Where your tumor is, and what that changes goes through the parts of the brain one at a time. It is written to an adult about their own scan, and it tells you how to read it for a child. It also says which part of it was written for adults: the part about surgery. And it says the signs of blocked fluid in a baby are different ones.

What symptoms does it cause in a baby or young child?

A toddler cannot tell you they have a headache. So the things you notice are behavior and body, not descriptions.

The signs to look out for:

• A head that is growing faster than it should, or a soft spot that looks full or pushed out.
• Throwing up, often in the morning, sometimes with a child who seems better afterwards.
• Being much sleepier than usual, or harder to wake.
• Being very unsettled or irritable, or not seeming like themselves.
• Feeding badly, or losing skills they already had.
• Trouble with balance or walking, or being unsteady and clumsy.
• Unusual eye or face movements.

Seizures can happen too.

A head growing faster than it should is a reason to call, not a reason to wait. No source we found puts an hour on it, so this page does not invent one. Only one of the hospital pages about this tumor gives any instruction at all, and it is plainer than a tier: if something has changed and you are worried, do not wait, call a doctor or get your child seen.

Symptoms can build quickly, so a short history is not a reason to wait and see.

The signs that mean going in now

These rules come from the signs, not from the tumor. That is worth saying out loud. The organizations that write about ATRT describe the symptoms and do not tell you when to go to an emergency room. The clear emergency advice that does exist is written about particular warning signs, and that is what is below.

A soft spot that is bulging while your baby is calm and sitting up means going in now. Call 911 or go to the nearest emergency room. A soft spot often looks full when a baby is crying, lying down or throwing up, and that is ordinary. The test is what it does when your baby is settled and held upright. If it goes back to soft and flat, that is the normal kind. If it stays bulging when your baby is calm and upright, that is the emergency. It matters more if there is also a fever, or your baby is very drowsy.

Rising pressure inside the head is treated as an emergency in its own right. Cleveland Clinic says to go to the nearest hospital for it, and names a brain tumor as one of the things that can cause it. In a baby it names drowsiness, a bulging soft spot, and throwing up. Those signs are printed here rather than left on the page they come from. A rule you cannot match to something you can see is no use at two in the morning.

If your child has a shunt, the rules change and get stronger. A shunt is a thin tube that drains the fluid. Three things are worth knowing by heart.

• If you cannot wake your child, go to the nearest emergency room right away, or call 911.
• If you think the shunt is infected, tell your neurosurgeon immediately, or go to the emergency room. Signs include a fever, or redness or swelling at the shunt site.
• If you think the shunt has stopped working, get medical help immediately. Being hard to wake or hard to keep awake needs urgent attention whatever your child's age.

Shunts and hydrocephalus has the fuller list of signs that a shunt is not working.

When in doubt, make the call. You know your child better than any page does, and a parent who calls about nothing has still done the right thing.

The general list below speaks straight to a patient. Your child is that patient, so every "you" in it means them. Parts of it were written with adults in mind and will not fit a baby at all.

When to call for help right now

Some things should not wait for the next appointment.

Call an ambulance for any of these. Call 911, or your local emergency number:

• A first ever seizure.
• A seizure that lasts more than five minutes.
• One seizure right after another, with no waking up in between.
• Someone who cannot be woken.
• Trouble breathing, or someone who seems to be choking.
• Suddenly not being able to speak, move one side, or see.

A seizure like the ones you usually have, that stops on its own, is not an ambulance call. What to do during a seizure draws the line.

Call your team the same day for any of these:

• A headache much worse than usual, or one that wakes you from sleep.
• Throwing up again and again.
• New weakness in the face, an arm or a leg.
• New trouble speaking, or understanding what people say.
• New confusion.
• Sleeping much more than being awake.
• A sudden change in your vision.

If you are having chemotherapy, a fever is its own rule. It means calling your team right away, at any hour, not waiting for the morning. An infection during chemotherapy can get dangerous fast, and it is treatable when it is caught early. The fever rule explains why, and what number your team will give you.

In the weeks after brain surgery, a fever is its own rule too, especially with a stiff neck or a bad headache. What comes after a craniotomy has the rest of that list.

If you have a shunt, the signs it has stopped working are their own rule. For you, everything on the same-day list above is a right-away call instead, and so are a few other signs. Get help right away, at any hour: call your team, or go to the emergency department. Signs a shunt is not working has the full list.

If you are not sure whether to call, call. Nobody on that team minds a phone call that turns out to be nothing.

Same day means today, not the next clinic appointment. Ask your team now for the after-hours number, and put it somewhere you will find it at two in the morning rather than somewhere sensible.

What to do during a seizure has the step-by-step, and getting help now is the short version to keep on a phone.

If the tumor is in the spinal cord, or has spread to the spine, new signs from the cord are their own rule. For you, an arm or a leg that is newly weak, or weaker than it was, is a right-away call, not a same-day one.

So are new trouble walking, new numbness or tingling, new or worse pain in the back or neck, and new trouble controlling the bladder or bowel. When cancer presses on the spinal cord, Cancer Research UK calls it an emergency that needs treating quickly. Call your team right away, at any hour, or go to the emergency department.

That last rule applies only where the growth sits in your child's cord, or has spread down into it. This tumor moves in spinal fluid, so it may well be yours. Ask your team if you are unsure. And one line of it reads differently in a very young child: a change in bladder or bowel control is hard to judge in a child who is not toilet trained yet. If something about that has changed, describe what you have seen rather than trying to decide whether it counts.

How do doctors find out it is this?

• An MRI scan of the brain, plus a separate one down the cord. That second picture is taken because this tumor can travel in the fluid. Some children are given medicine to help them sleep through a scan. Many children manage without. When your child has a brain tumor covers what that is like.
• An operation, or a piece of the tumor. The tissue that names the tumor comes from surgery. Your pathology report unpacks the document that comes back.
• A test of the spinal fluid. A small amount of fluid is taken, usually from the lower back, and the laboratory looks for tumor cells in it.
• Gene tests on the tumor tissue. These are what confirm the diagnosis. See below.
• An ultrasound of the kidney. There is a good reason for it. The same gene change can cause a tumor of the kidney, so the kidney may be checked too.

The gene test is the one that settles it. This tumor is defined by a missing gene, not by how the cells look. The usual one is called SMARCB1, which you may also see written INI1. Less often it is a gene called SMARCA4, also written BRG1.

What the laboratory actually looks for is a missing protein. The tumor cells have lost it, while the normal cells around them still have it. That pattern is what confirms ATRT.

Waiting for results deals with the delay itself, which most families find harder than the tests.

What do the words on my child's report mean?

The rules for naming brain tumors changed in 2021. If your paperwork was written before that, some of its words are no longer used.

This matters more than it sounds. People read an old report next to a new one, see two different names, and think somebody made a mistake. Usually nobody did. The tumor did not change. The way doctors write it down changed.

Three changes affect almost every report.

• Roman numeral grades, such as grade II or grade IV on an older report. These are now written with ordinary numbers instead: grade 2, grade 4. Nothing about the grade itself changed. Only the way of writing it did.
• Gene results are now part of the name. Older reports named a tumor mostly by how the cells looked. A name written now usually has a gene result built into it. That is why a newer report can look longer and more technical than an older one about the same tumor. You may also see NOSNOS: Short for "not otherwise specified". It means the gene tests needed to name the tumor fully were not done or could not be done. Ask your team whether they can be. See the glossary or NECNEC: Short for "not elsewhere classified". The tests were done, but the results do not match any named tumor type. Ask your team what it means for your plan. See the glossary written next to your diagnosis. These say something about the testing, not about how serious the tumor is. NOS means the tests needed to be more exact were not available. NEC means testing was done, but the results did not fit any defined group neatly.

Seeing an older name on your own report does not mean it was wrong. It means it was written under the old rules. If you are holding an old report and a new one and they do not match, that is a good thing to take to your team and ask about.

There is no official stage for this tumor

This one trips people up. You may see staging words on your child's report, and there is no agreed staging system for ATRT. The National Cancer Institute says so plainly. So the words describe what was found. They are not steps on an official ladder.

What your team sorts by is simpler than a stage. The National Cancer Institute groups this tumor as newly diagnosed or as one that has come back, and says treatment turns on your child's age, how much of the tumor is left after surgery, and whether it has spread to other parts of the brain and spine.

One word is worth knowing, because it is where this tumor tends to go.

• Leptomeningeal means cells were found in the spinal fluid and the thin coverings around the brain and cord. St. Jude describes that as where ATRT usually spreads.

In some children it has already spread by the time it is found. Published figures put that at somewhere between about one in seven and one in three. It usually spreads through the spinal fluid. That is why the spine scan and the fluid test are done at the start rather than later.

If you see a letter and a number, such as M and a digit, ask your team what it means for your child. That shorthand is borrowed from another tumor, and no source applies it to this one.

Older names, and names that are not this tumor

• PNET, or primitive neuroectodermal tumor. This name is retired. Before the gene test existed, this name covered many tumors now known to be different. The gene test is what separated them.
• Rhabdoid tumor. This is the family name. The same kind of tumor can grow in the kidney or elsewhere in the body. ATRT is the one in the brain and spine.
• ETMR is a different embryonal tumor, not this one, and it is defined by a different gene change.

How is it usually treated?

Treatment is intensive, and it usually has three parts.

An operation is usually the opening move. The goal is to remove as much as the surgeon safely can, and how much that turns out to be depends on where the growth sits and what lies beside it. What an operation involves covers the rest.

Blocked fluid may need to be relieved as well. Your team may use a short-term drain, or a shunt.

Chemotherapy comes next, and it is strong. Two things about it are specific to this tumor.

• Medicine is often put straight into the spinal fluid. Boston Children's Hospital calls this an important part of treatment, because it delivers the medicine directly to the spinal fluid, which is where this tumor travels. It is given either through a small reservoir placed under the scalp, or by an injection in the lower back.
• Some children have very high doses, with their own stem cells given back afterwards. The team collects some of your child's own blood-forming stem cells first, and they are frozen for later. The high doses damage the bone marrow, and giving the cells back lets it recover.

Radiation is the part that turns on your child's age, and this is the decision parents ask about most.

• Under 3, radiation is often reduced, aimed at a smaller area, or left out altogether. Radiation affects a brain that is still developing.
• Over 3, it is generally part of standard treatment.
• You may hear about proton therapy. Ask what your team would expect it to spare, and whether they would use it for a child this young.

Ask your team where they draw that age line, and why.

Ask about a clinical trial early, because here it is the usual route rather than a last resort. One US children's hospital says most children with this diagnosis are treated as part of a brain tumor trial. There is also a registry just for this tumor, which collects information to help research on a cancer too rare for any one hospital to study alone. Clinical trials covers how to think about one.

A note on the three types you may read about. Researchers sort ATRT into three groups using a laboratory test on the tumor's DNA. Today that mostly helps research and trials. Specialists say plainly that what those groups mean for treatment is still unsettled.

What is treatment actually like, and what is normal afterwards?

After surgery low at the back of the brain

About half of these tumors grow in the lower rear of the brain, the cerebellum or the brain stem. This part is for you if your child was operated on there. That is not the same as where the tumor sits, because what can be removed, and how, depends on the exact spot. Doctors call what can follow that operation posterior fossa syndromeposterior fossa syndrome: Something that can happen after an operation on the lower back of the brain. Some children cannot speak for a while. Swallowing, walking and mood can change too. It always starts in the first week after surgery. See the glossary.

A day or two after surgery low at the back of the brain, some children stop talking. It can also change swallowing, walking, mood and behavior. It always starts within the first week.

Suddenly not being able to speak is on the ambulance list above, and that rule still stands. What this section describes usually starts in the hospital, in the days right after the operation, where the team is watching for it.

It is frightening to see. Doctors know it as a complication of the operation itself. Most children slowly get better. Speech usually comes back over days or weeks, and for some it takes months. Most children walk on their own again. Some trouble with speech, movement or mood can last longer, even years. Speech therapy can help. If the swallowing, walking, mood or behavior changes start or get worse after you are home, call your team the same day, or right away if there is a shunt.

How often it follows an operation for this particular tumor is not published. The clearest hospital pages about it were written for different growths in that same region. It is reported after this operation, whatever the growth was. Before the operation, ask your surgeon what they have seen and what they will be watching for.

The everyday mechanics

Your child may have a central line. It is used for children who are seriously ill and need treatment for a long time. It is a soft tube that stays in, and it means fewer needle sticks for medicines, fluids and blood samples. Keeping the site clean and dry becomes a daily job, and washing your hands before and after any line care is not a formality.

Blood counts fall after chemotherapy and then recover. When they are low, a common cold is not a small thing. A fever during treatment means telling your team right away, whatever the hour. You will not always know whether the counts are down. Your team will give you the reading that counts as a fever, and it is theirs rather than one from a page. The fever rule explains why teams differ.

Eating can become a problem, and a feeding tube is a common procedure in children with cancer. It is not a defeat. It is how a small child gets through a long stretch of treatment without losing ground, and good nutrition matters for growth, energy and healing.

Hearing is tested, and not just as a precaution. Two of the medicines used here, cisplatin and carboplatin, can damage hearing, and high sounds are affected first. In a child who is still learning to talk, hearing affects speech and development, and finding a problem early is what lets somebody act on it. Ask when your child's hearing will be tested and how often.

Everyday life: feeding, development, hearing and school

This section is about a child who is still learning everything, which is what makes it different from the same section on any adult page.

Development is the thing to watch, and to act on early. Treatment at this age can slow how fast new skills are picked up. Often the issue is not that your child loses what they had. It is that new things come more slowly than they would have.

Early intervention is the most useful thing on this page. Support exists for very young children. St. Jude puts it plainly: early intervention and paying close attention to symptoms can help. When your child has a brain tumor sets out the two school routes for the years ahead, and says that children under 3 come under a different part of the law behind one of them, for early intervention. Ask your team who makes that referral.

Hearing again, because it connects to speech. If hearing is affected, finding it early is what lets somebody do something about it while your child is learning to talk.

School comes sooner than it feels. Ask the hospital who helps with school before you need them.

Nothing in this section is about driving, work or money, which the same section carries on the adult tumor pages. They will matter one day. They do not matter this year, and pretending otherwise would waste your attention.

Follow-up scans, and what to do while you wait

Follow-up carries on after treatment ends. Your team sets the rhythm. No published schedule exists for us to point you to, so ask yours for theirs and write it down.

Scans are not the whole of follow-up. Hearing and hormone levels are checked as well.

Follow-up scans explains what a new picture gets measured against, and waiting for results covers the stretch before an answer arrives, which many families find worse than the scan itself.

If something new appears, report it that day instead of storing it up for the next visit.

If it comes back, or changes

There is no standard treatment for this tumor if it comes back, and a major US cancer center says exactly that. The same center says a trial is how children reach the treatments that are still being tested.

Ask your team what they would weigh: which treatments your child has already had, where the growth has appeared, and how they are doing now.

Ask what the aim of any new treatment would be, and write the reply down as it comes. The purpose is not always what it was the first time around, and asking that outright is entirely fair.

Did I cause this?

Before the general answer below, one thing is specific to this tumor, and it runs the other way.

For ATRT, an inherited gene change is more common than it is for most brain tumors. Roughly one child in four to one in three with a rhabdoid tumor was born with a change in the gene involved. That is not most children, and it is not rare either.

This is why every family should be offered genetic counseling. Cancer genetics experts recommend that every child diagnosed with this tumor is referred, whatever the family history. A genetic counselor explains what a test would and would not tell you, and helps you decide whether anyone else in the family should be tested.

If your child does carry that change, it has a name: rhabdoid tumor predisposition syndrome. It matters because the same change can cause tumors elsewhere, most often the kidney. Some teams then recommend a brain MRI and an ultrasound of the belly at diagnosis, and regularly afterwards. How often is not set, so ask yours.

None of that means anybody did anything. A gene change you were born with is not a choice anybody made. If it turns out a parent carries it too, that is information for looking after your family, not a verdict on anyone.

Almost everybody asks this, usually in the first week, usually in private. It is worth answering plainly.

For most brain tumors, nobody knows the cause. That is the honest state of it. The exact cause of most brain and spinal cord tumors is not fully understood, and there are very few well established risk factors. Tumors start when genes that control how cells grow and divide are changed, and in most cases those changes happen by chance during a person's life. Not because of something done or not done.

Cell phones. They give off a kind of radiation called radiofrequency. It is not the same as the radiation in an x-ray. The energy is too low to damage DNA, and it is not known to cause cancer. The evidence so far is that using a cell phone does not cause brain tumors.

Stress. There is no scientific evidence that stress causes brain tumors, and no data linking stress to a higher chance of getting one. A hard year before a diagnosis is a hard year. It is not a cause.

Something you ate, or did not eat. No food and no diet is an established cause of a brain tumor. It is not on the list of known risk factors at all.

Something you passed on, or caught. Brain tumors are not contagious. Most are not inherited either. A small number of people do have an inherited condition that raises the risk, and if that applies to you, your team will raise it and offer to talk it through.

If you are turning this over at three in the morning, that is ordinary and it happens to nearly everyone. It is also worth saying out loud to somebody on your team, because they have answered it many times and they would rather you asked.

What might happen over time

For the person caring for someone with this

If you are the one driving to the appointments, keeping track of the pills, and lying awake at night worrying about them, this part is for you.

You are allowed to ask questions. In one study, families said they were afraid of annoying the doctor by asking too much. One of them was told by a doctor to stop playing doctor. Ask anyway. Write your questions down before you go, and bring a notepad. Two people in the room hear more than one.

Ask who your first call is. Care comes from a lot of people at once, and it is easy to end up as the only one holding it together. Ask the team: who do I call first? Some teams have one person whose job this is, often a nurse. Get the name and the number.

Get two numbers, and know which one to use. One for work hours, one for nights and weekends. Then ask what counts as "call us today" and what counts as "call an ambulance" for this tumor, and write the answer down where you can see it. If you are not sure which it is, call. Nobody on that team will mind.

If they have seizures, read about them before you need to. What to do when someone has a seizure is the one to know by heart. Living with seizures is about the rest of the time: what is safe, what to change, and driving.

Ask to be shown anything you are sent home to do. In that same study, families were sent home to change dressings and give medicines with no training at all. That is not fair to you. Before you leave the hospital, ask someone to show you. Then do it once while they watch.

Say what you notice. You may see a change before they do. Changes in thinking, mood and behavior can show up to the people close by first. Telling the team is not going behind their back. It is something the team cannot learn any other way.

Look after yourself, and let people help. Eat, sleep, and keep your own appointments. Take a little of the day back for yourself. When someone asks what they can do, give them a real job: a meal, a ride, an hour with the kids. Most people want to help and do not know how to offer.

You can talk to somebody about all of this today. See where to get help.

Four things specific to this diagnosis.

Almost everyone reading this is a parent of a very small child, so the whole of the section above is written to you rather than about somebody else. Asking your team to go over the same ground twice is completely reasonable.

Two to know by heart, and the rest are in the signs that mean going in now: a soft spot that stays bulging when your baby is calm and upright, and a child with a shunt who cannot be woken. You may well spot either one before anybody else does, and acting on it is not overreacting.

One of you may end up living at the hospital. Where high-dose treatment with stem cells is used, stays are long, a caregiver is expected to stay, and it is better if more than one person is trained to do the care. Work out early who that second person is.

Brothers and sisters need telling too. Some may believe they caused it, so St. Jude tells parents to say plainly that nothing anyone can think, say or do makes someone else get sick. It also suggests keeping school and hobbies going, and saying out loud that they are being brave as well.

What to ask your team

• What is my child's tumor called, and is there a gene result yet?
• Has the spine been scanned, and has the spinal fluid been tested?
• Was the whole growth removed, and what did the scan afterwards show?
• Will treatment include medicine into the spinal fluid, and how will it be given?
• Is high-dose treatment with my child's own stem cells part of the plan?
• Where do you draw the age line for radiation, and why?
• Is proton therapy an option for us?
• Is there a clinical trial or a registry we should be talking about?
• Should our family see a genetic counselor, and when?
• Does my child need a kidney ultrasound, and how often?
• When will hearing be tested, and who follows it up?
• Who refers us for early intervention, and can we start now?
• What number do you use for a fever, and who do we call after hours?

Where to get support

• Getting help now lists who to call and when.
• Hope4ATRT is a US charity for this exact tumor, with help on travel, money and finding trials.
• The American Childhood Cancer Organization runs free peer support for families, including online support that is there at any hour, and a section for brothers and sisters.
• When your child has a brain tumor covers what is different about childhood brain tumors generally, including school and talking to your child.
• Medulloblastoma if your child's report turns out to name that instead.
• Your child's specialist nurse, who can usually get you an answer sooner than anyone else on the team.