Diffuse midline glioma

A fast-growing glioma in the middle of the brain or in the spinal cord. It is named after a change written H3 K27. What the name means, and why it is always grade 4. How DIPG fits in, and what treatment is for.

The short version

A diffuse midline gliomaglioma: A tumor that starts in the glial cells. Those are the support cells of the brain and spinal cord. Gliomas are given a grade from 1 to 4. The grade says how the tumor is expected to act. See the glossary is a fast-growing tumor in the middle of the brain or in the spinal cord. It is named after a change written H3 K27, and it is always grade 4. When it sits in the pons, a part of the brain stem, it is often called DIPG, and DIPG is the page written for that. Radiation is the main treatment. Ask about clinical trials at the start, without holding up radiation your team says is urgent.

What is a diffuse midline glioma?

It is a tumor that starts in the brain's helper cells, so it is one kind of glioma. It grows in the middle parts of the brain and spine: the brain stem, the thalamusthalamus: A part deep in the brain, near its center. It passes messages from the senses and the body on to the rest of the brain. See the glossary and the spinal cord.

Diffuse means it grows out into the healthy tissue around it, like fingers, rather than sitting in one lump. That is the fact most of this page follows from.

It is found most often in children. It also happens in adults, where it is less common and most often in the thalamus.

DIPG, and why it is not another word for this

DIPG stands for diffuse intrinsic pontine glioma. It is an older name for one of these tumors when it sits in the pons. So most tumors called DIPG are diffuse midline gliomas. But one in the thalamus or the spinal cord is not a DIPG.

Some websites say this tumor "used to be called DIPG". That is only true of the ones in the pons.

Is it cancer? What does its grade mean?

Yes. A diffuse midline glioma is cancer. The word your team will use is malignant.

It is always grade 4. Grade 4 is the top of the scale.

This tumor grows into the healthy tissue around it, so there is no edge to cut around. With today's treatments, it is not curable. That is a hard sentence, and it is here on purpose, because hearing the grade without hearing this can leave people shocked later.

Not curable is not the same as untreatable, and it is not a timeline. Treatment can ease symptoms and slow the tumor for a time, and there are still choices if it grows.

But the cells did not look grade 4

This surprises people, and it is not a mistake. Since 2016, a tumor with this name is grade 4, even when the cells under the microscope look like a lower grade.

You may read that one of these can look low grade. That is about how the cells look. It does not change the grade of a tumor with this name.

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

It grows in the middle of the brain or in the spinal cord, and where it sits decides what you notice.

• In the pons, part of the brain stem, the stalk the brain sits on. The nerve paths for eye movement, hearing, speech, swallowing and balance pass through it. So do the paths for movement in your arms and legs.
• In the thalamus, deep in the middle of the brain. What you notice depends on the exact spot, so ask your team which of your symptoms it explains.
• In the spinal cord. Here it can cause weakness, numbness, and trouble with the bladder or bowel.

In the brain, it can also stop fluid draining away. The section below explains what that does.

Most people are told what they have long before anyone explains what it is doing. These are the ways a tumor in the brain causes symptoms. They overlap, and most people have more than one going on at once. Which of them apply to you depends on what your tumor is and where it sits.

It takes up room. The skull is a closed box. It cannot stretch. So anything new inside it has to push on something. The tumor and any swelling around it together take up space and press on nearby parts of the brain.

It can make the brain around it swell. This one surprises people, and it is worth understanding. Fluid builds up in the brain tissue near the tumor. That swelling plays a major part in deciding what symptoms you get. Some of what you are feeling may not be the tumor itself. It may be the swelling around it. That is why medicines that bring swelling down can change how somebody feels, without the tumor being any different than it was.

Pressure can build up inside the head. When the pressure inside the skull rises, there is a pattern doctors watch for: headaches that are worse in the morning, feeling sick to your stomach and throwing up, odd eye movements, seizures, and being confused or very drowsy. Not everybody with raised pressure has all of it, and some people have almost none of it. If this pattern is new for you, it is worth a phone call rather than a wait. If you have a shunt, it means getting help right away.

It can set off seizures. A tumor and the irritated brain around it can upset the normal electrical activity of that part of the brain. For some people a seizure is the first sign that anything is wrong.

It can block the flow of fluid. The brain makes a fluid that circulates around it and drains away. A tumor sitting in the wrong place can block that flow, so the fluid backs up and the pressure goes up. This is more likely with tumors near the narrow channels the fluid passes through. It can be treated, and the usual treatment is a shunt. That is a thin tube that carries the fluid to another part of the body, where it is absorbed. It is the word your team will use. Shunts and hydrocephalus covers what having one is like, and the signs it has stopped working.

Why your symptoms are the ones you have

The short rule: the symptom tells you where, the scan tells you what. A tumor disturbs whatever job the brain does in that spot, so where it sits decides what you notice.

There is one exception, and it is the fluid. When the flow is blocked, what you notice is the pressure rather than the spot: headaches worse in the morning, throwing up, double vision, and feeling unsteady. Those signs are much the same wherever the blockage sits, so they tell you the pressure is up, not where the tumor is. If that is your pattern, the part above called It can block the flow of fluid is the one about you, and it says what can be done. If the pattern is new, the phone call above applies.

• Front of the brain. Personality, behavior, planning, motivation, and on one side, producing speech.
• Side of the brain, near the temple. Seizures, memory, and understanding what people say.
• Upper back part of the brain. Sensation, knowing where your body is in space, reading, writing and arithmetic.
• Back of the brain. Vision, and losing part of your field of view.
• Cerebellum, low at the back. Balance, coordination and walking.
• Brainstem. Double vision, facial weakness, and trouble swallowing.
• Deep in the middle, near the spaces the fluid runs through. A tumor here can block the flow, so what you notice is often the pressure rising rather than anything that points to the spot.
• The floor of the skull, below and behind the ear. Hearing, balance, and the nerves to the face. So hearing loss or ringing in one ear, dizziness, and numbness or weakness down one side of the face. Your team may call the whole floor of the skull the skull base. This spot is one part of it.
• Behind the eyes, at the base of the brain. Vision, and the hormones that set energy, weight, thirst and periods. In a child, growth and puberty too. Side vision is what usually goes first, so things start disappearing at the edge. Your team may call this the pituitary or the sellar region.

If something on this list matches what you have noticed, it is worth writing down and taking to your next appointment. Your team can tell you whether it fits where your tumor actually is.

This list is about what the place explains. The other half of the question is what the place changes: whether an operation is offered, how much of it can come out, and when the place makes something urgent on its own. Where your tumor is, and what that changes is that half.

What symptoms does it cause?

In the brain stem, the commonest are:

• Double vision, or eyes that do not move together.
• One side of the face drooping.
• Trouble with balance or walking.
• Drooling, or trouble swallowing.
• Slurred speech.
• Weakness in an arm and a leg on one side.

From pressure inside the head: headaches that are worse in the morning, nausea and throwing up, and being very sleepy.

In the spinal cord: weakness that keeps getting worse, numbness, and trouble controlling the bladder or bowel. For a tumor in the spinal cord, these have their own rule, at the end of the section on when to call for help, below.

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.

How do doctors find out it is this?

A scan first, and then, more often now, a piece of the tumor.

• An MRI scan. For a child with the typical picture in the pons, the scan can be enough to start treatment. DIPG explains that choice.
• In adults, a scan alone cannot make this diagnosis, because the tumor can look like other fast-growing brain tumors.
• A tissue sample, by a needle biopsy or during an operation, tested for the H3 K27 change.

Biopsy is done more often than it used to be. Part of the reason is that many clinical trials, and the newer drug below, need that gene result.

What do the words on my 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.

The results that matter most on this report:

• Diffuse midline glioma, H3 K27-altered. The full current name. The gene change is part of the name.
• Grade 4. Always, for this name.
• H3 K27M. An older way of writing it. Both may describe the same tumor, and that page explains why there are two.

Your pathology report walks through the document itself.

If your older paperwork says something different

• Diffuse midline glioma, H3 K27M-mutant. The 2016 name for the same tumor. It does not change your diagnosis.
• DIPG, or brain stem glioma. Older names that said where the tumor sat. Brain stem glioma can also include low-grade tumors that are not this one, so it is worth asking which yours is. If yours is in the pons, DIPG is the page for you.

How is it usually treated?

A tumor board is a meeting where specialists look at one person's case together: surgeons, cancer doctors, the lab, and the people who read scans. It tends to happen when a case is complicated or something is hard to read.

You do not go to the meeting. Afterwards, the doctor who knows you best explains what was said.

What they decide is advice, not an order. The choice is still yours. Because you are not in the room, tell your team what matters to you before it happens, so it is taken into account.

• Surgery, where it can be done safely. In the pons it cannot be done safely, because the tumor grows into parts the body cannot do without. Elsewhere, taking some of it out may be possible.
• Radiation is the main treatment.
• Steroids to bring down swelling.
• A shunt, if the fluid around the brain is blocked.

Chemotherapy, and one honest note about it

The chemotherapy drugs used for other gliomas have not been shown to help this one. Some teams still give it, in a trial or outside one, and there is no standard plan. If it is offered, it is fair to ask what it is meant to do.

Dordaviprone, the drug for this gene change

Dordaviprone is a capsule taken by mouth once a week. Its brand name is Modeyso. In 2025 the FDA approved it for adults and children aged 1 and over with a diffuse midline glioma that has the H3 K27M change and has kept growing after other treatment.

It was given accelerated approval. That means it was approved early, based on how many tumors shrank and for how long. Trials are still checking whether it helps people live longer. Until they report, nobody can tell you that it does.

Most of the people in the studies behind the approval were adults. Those studies also left out DIPG and tumors that started in the spinal cord. So for a child, or for a tumor in one of those places, ask your team what they know about it.

It needs the gene result, so ask whether yours was tested. Targeted drugs covers what being on it involves. If the tumor is in the pons, DIPG has more on it.

Clinical trials, and why to ask early

Some trials start at diagnosis, some after radiation, and some later. Asking at the start keeps the most options open, as long as it does not hold up radiation your team says is urgent. Ask your team which clinical trials you or your child could join, and what testing that needs.

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

The library pages carry the detail: what radiation is like, what steroids do and how a biopsy is done.

Steroids change how someone looks. Weight gain and a round, puffy face come mainly from the medicine, not from the tumor. Steroids goes through the rest of what they do.

Palliative carepalliative care: Care that helps with pain and other symptoms. It supports the whole family too. It can start early. It includes help with making choices about treatment. See the glossary is worth meeting early. The word can sound like giving up. It is not. The team is meant to be there from the start.

Everyday life: school, work, seizures and tiredness

• Living with seizures covers the practical side, and what to do during a seizure is worth reading before you need it.
• Driving rules depend on where you live. Ask your team directly.
• Tiredness is common during and after radiation. It can come from the treatment, and it can also come from the tumor. Sleeping much more than being awake is a same-day call, or a right-away call if there is a shunt.

Ask early who at the hospital helps with school, work and money.

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

Scans continue after treatment. Follow-up scans goes through what each scan is compared with, and waiting for results covers the gap before the answer.

If it comes back, or changes

If the tumor grows again, there are still choices. Your team may talk about a clinical trial, dordaviprone, radiation again, or care that focuses only on comfort.

Radiation a second time is something doctors disagree about. For DIPG, St. Jude says it can be done safely, though the benefit is more limited. A 2022 review of DIPG says it can help slow the tumor, but it has significant risks and burdens, and is not usually recommended. Ask your team whether it is an option for you, and what it would be for.

No choice here is the wrong one. Ask your team what each option is for, and write the answers down.

Did I cause this?

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.

Will my other children get this? This tumor is not passed down in families. It is nobody's fault, and nothing done in pregnancy or early childhood has been shown to cause it.

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.

Two things specific to this diagnosis.

Many people caring for someone with this tumor are parents. Everything above still applies, and so does asking early for the palliative care team. That team is there for the whole family.

If the tumor is in the brain stem, watch swallowing. New trouble swallowing, or new drooling, means calling your team the same day. Food or drink can go down into the lungs. Choking, or trouble breathing, is an ambulance call.

What to ask your team

• Where exactly is the tumor, and is it in the pons?
• Was it tested for the H3 K27 change? Was a biopsy done, and if not, why not?
• What is radiation meant to do, and how long will it take?
• Is chemotherapy being offered, and what would it be for?
• Is dordaviprone an option now, or later?
• Which clinical trials could we join, and do any of them need to start before radiation?
• When should we meet the palliative care team?
• What should we know about the steroids, and what is the plan for coming off?
• What would make you want to see us before the next appointment?
• Who do we call after hours, and what number is it?

Where to get support

• Getting help now if you need somebody today.
• My DIPG Navigator, from the ChadTough Defeat DIPG Foundation, has nurse navigators who help families facing DIPG and diffuse midline glioma.
• The International DIPG/DMG Registry has pages written for families.
• What to do during a seizure, worth reading before you need it.
• Living with seizures for the practical side.
• Your team's specialist nurse, who is usually the fastest way to get a question answered.