DIPG (Diffuse Intrinsic Pontine Glioma)

What is DIPG (Diffuse Intrinsic Pontine Glioma)?

DIPG, short for diffuse intrinsic pontine glioma, is a rare and aggressive brain tumor that grows in the pons. The pons is a part of the brainstem, the structure that connects the brain to the spinal cord. The brainstem controls many functions the body performs without thinking about them, including breathing, heart rate, swallowing, eye movement, facial movement, and balance. Because the pons is packed with these vital nerve pathways, even a small tumor in this area can cause serious symptoms.

The name describes the tumor itself. “Diffuse” means the tumor spreads through healthy tissue rather than forming a separate lump with clear edges. “Intrinsic” means it grows from within the pons rather than pressing on it from outside. “Pontine” refers to the pons. “Glioma” means the tumor arises from glial cells, which are the supporting cells of the brain and spinal cord. In current medical classification, most DIPG tumors fall under a broader group called diffuse midline glioma, H3 K27-altered, named after a genetic change found in the tumor cells.

A DIPG brain tumor is almost always a childhood cancer. It most often affects children between roughly 5 and 10 years of age, although it can occur in younger children, teenagers and, rarely, adults. It affects boys and girls at similar rates. DIPG is considered a high-grade tumor, meaning it grows quickly and behaves aggressively. It is one of the most difficult childhood brain tumors to treat, largely because it cannot be surgically removed without damaging the brainstem.

Symptoms of DIPG

DIPG symptoms usually appear over a short period, often within weeks to a few months, and tend to worsen steadily. This rapid onset is one of the features that distinguishes DIPG from slower-growing brainstem tumors. Symptoms result from the tumor disrupting the nerves that pass through or originate in the pons.

Doctors often describe a classic group of three types of problems in DIPG:

• Cranial nerve problems: double vision, eyes that do not move together or appear crossed, drooping of one side of the face, difficulty swallowing, slurred speech, or changes in hearing.
• Coordination problems (ataxia): unsteady walking, clumsiness, frequent falls, or trouble with fine movements such as writing or buttoning clothes.
• Weakness (long-tract signs): weakness or stiffness in an arm or leg, often on one side of the body, or abnormal reflexes noticed during an examination.

Other DIPG symptoms may include:

• Headaches, often worse in the morning or on waking.
• Nausea and vomiting, particularly in the morning.
• Unusual tiredness or drowsiness.
• Changes in behavior, mood or school performance.
• Difficulty controlling the eyes, such as rapid, jerky eye movements (nystagmus).
• Drooling or food and drink coming back through the nose.
• Abnormal breathing patterns or changes in heart rate in advanced disease.

Not every child has all of these symptoms. Some children first show only one problem, such as a new squint or a change in the way they walk. Because many of these signs can also occur in common childhood illnesses, they are sometimes attributed at first to an ear infection, a viral illness or clumsiness. The pattern that concerns doctors is a combination of several of these symptoms appearing together and getting worse over a few weeks.

Headaches and vomiting can also occur if the tumor blocks the flow of cerebrospinal fluid, the clear fluid that cushions the brain. This blockage causes a build-up of fluid called hydrocephalus, which raises pressure inside the head. Hydrocephalus is less common with DIPG than with some other brain tumors but can develop as the tumor grows.

Causes and risk factors

The exact cause of DIPG is not known. Research over the past two decades has shown that most DIPG tumors carry a specific genetic change in the tumor cells, most often in genes called H3F3A or HIST1H3B, which produce histone proteins. Histones help package DNA inside the cell and control which genes are switched on or off. The change, known as the H3 K27M mutation, appears to disrupt normal cell development in the developing brainstem and allow cells to grow uncontrollably. Other changes, in genes such as TP53, ACVR1 and PDGFRA, are also found in many tumors.

It is important to understand that these are changes that occur in the tumor cells themselves. They are not inherited from parents in the vast majority of cases, and there is no evidence that anything a parent did or did not do caused the tumor. Families should not blame themselves.

Known and suspected risk factors are limited:

• Age: DIPG occurs almost exclusively in children, with a peak in the middle childhood years. This suggests it is linked to normal brain development during this stage of life.
• Genetic syndromes: in rare cases, inherited conditions that increase the risk of many cancers, such as Li-Fraumeni syndrome, may be associated with brainstem gliomas. Most children with DIPG do not have such a syndrome.
• Prior radiation to the head: radiation therapy for another condition is a known risk factor for some brain tumors in general, although it is rarely relevant to DIPG.

There is no established link between DIPG and infections, diet, mobile phones, environmental chemicals, head injury or lifestyle. Because the cause is unknown and the tumor is rare, no screening test exists.

Diagnosis

Diagnosis of DIPG usually begins when a child is seen for a combination of neurological symptoms. A doctor will take a detailed history, asking when symptoms began and how quickly they have progressed, and will perform a neurological examination. This includes checking eye movements, facial strength, swallowing, speech, reflexes, strength in the limbs, and balance and walking.

The key test is magnetic resonance imaging (MRI) of the brain, usually with a contrast dye injected into a vein. MRI uses magnets and radio waves to produce detailed pictures of the brain. On MRI, DIPG has a characteristic appearance: the pons looks swollen and the tumor blends into surrounding tissue without clear borders, usually occupying more than half of the pons. Because this appearance is so typical, doctors have historically been able to diagnose DIPG from MRI findings and clinical symptoms alone, without a biopsy.

A CT scan (computed tomography, an X-ray based scan) may be done first in an emergency setting because it is quick, but MRI provides much more detail and is the standard imaging test.

A biopsy, in which a small sample of tumor tissue is removed and examined under a microscope, is increasingly performed at specialized centers. This is done using stereotactic techniques, meaning imaging is used to guide a fine needle precisely to the tumor through a small opening in the skull. Biopsy of the brainstem carries risks and is not performed everywhere, but it allows doctors to confirm the diagnosis, identify the tumor’s genetic changes, and determine whether the child may be eligible for a clinical trial of a targeted therapy. Your child’s medical team will discuss whether a biopsy is appropriate.

Other tests that may be used include MRI of the spine to check whether the tumor has spread along the spinal cord, and in some cases a lumbar puncture (spinal tap) to examine the cerebrospinal fluid. Blood tests do not diagnose DIPG but may be used to check general health before treatment.

Diagnosis and treatment planning are normally handled by a team that includes pediatric neuro-oncologists (doctors who treat childhood brain tumors), radiation oncologists, neuroradiologists and neurosurgeons. At Acibadem, brainstem tumors are managed jointly by the pediatric oncology and neurosurgery departments.

Treatment options for DIPG

DIPG treatment aims to control symptoms, slow the growth of the tumor, and maintain the best possible quality of life for as long as possible. At present, there is no treatment that reliably cures DIPG. Families should be given honest information about this so that they can make informed decisions.

Radiation therapy is the standard treatment. It uses high-energy beams directed precisely at the tumor over a course of daily sessions, usually lasting around six weeks. Radiation is the only treatment that has consistently been shown to improve symptoms and extend life in DIPG. Many children experience meaningful improvement in weakness, eye movement or walking during or after radiation, and this improvement may last for several months. Radiation does not eliminate the tumor, and in most cases the tumor eventually begins to grow again. Shorter courses of radiation are sometimes offered in specific circumstances, and repeat radiation at the time of regrowth is considered at some centers.

Steroid medication, most often dexamethasone, is commonly used to reduce swelling around the tumor. It can quickly relieve symptoms such as headache, vomiting and weakness. Steroids do not treat the tumor itself, and long-term use causes side effects including weight gain, mood changes, increased appetite, high blood sugar and muscle weakness. Doctors usually aim to use the lowest dose for the shortest time possible.

Surgery to remove the tumor is not possible for DIPG. The tumor is woven through the brainstem, which controls breathing and heart function, so attempting to remove it would cause severe harm. Surgery may still have a role in two situations: obtaining a biopsy, and treating hydrocephalus. If fluid builds up in the brain, a neurosurgeon may place a shunt (a thin tube that drains excess fluid to the abdomen) or perform a procedure called an endoscopic third ventriculostomy, which creates a new pathway for fluid to flow.

Chemotherapy, meaning drugs that kill rapidly dividing cells, has been studied extensively in DIPG. Standard chemotherapy drugs have not been shown to improve survival, partly because the blood-brain barrier limits how much drug reaches the tumor. Chemotherapy is therefore not part of routine care outside of clinical trials, although some doctors may offer it in individual situations.

Clinical trials are an important option for many families. Research is testing targeted drugs that act on the specific genetic changes in DIPG cells, immunotherapies that help the immune system recognize the tumor, and new ways of delivering drugs directly to the brainstem. Some newer agents have shown encouraging early results and may be available in certain settings. Your child’s team can explain which trials may be relevant and what participation would involve.

Supportive and rehabilitation care runs alongside all other treatment. Physical therapy helps with strength and balance, occupational therapy helps with daily tasks, and speech and language therapy supports swallowing and communication. Palliative care specialists, who focus on comfort and quality of life at any stage of illness, are often involved early and work with the family to manage symptoms and support emotional wellbeing. Involving palliative care does not mean that other treatment has stopped.

Living with DIPG (diffuse intrinsic pontine glioma) and outlook

Families searching for the DIPG survival rate deserve a straightforward answer. DIPG has one of the poorest outlooks of any childhood cancer. In most cases, the disease progresses within months of diagnosis despite treatment, and the majority of children do not survive beyond two years. A small number of children live longer, and researchers study these cases closely to understand why. Survival statistics describe groups of patients and cannot predict what will happen to an individual child. Your child’s medical team is the best source of information about their particular situation.

After radiation therapy, many children have a period of relative stability, often lasting several months, when symptoms improve and they can return to some normal activities such as school, play and time with friends. Families often describe this as an important time. Planning for how to use it, whether through travel, celebrations or simply ordinary routines, is a personal decision that the care team can support.

As the tumor grows again, symptoms typically return and progress. Weakness, difficulty swallowing, changes in breathing and increasing sleepiness are common in the later stages. The care team will focus on keeping the child comfortable, managing pain and other symptoms, and supporting the family. Many families find it helpful to discuss their wishes about care in advance, including where they would prefer their child to be cared for.

The emotional impact on parents, siblings and extended family is profound. Psychological support, social work services, parent support groups and, where wanted, spiritual care are usually offered through the treating hospital. Siblings often benefit from age-appropriate explanations and their own support. Practical help with finances, work leave and travel is also available in many health systems.

Frequently asked questions

What is the DIPG survival rate?

DIPG is among the childhood cancers with the poorest prognosis. Most children live for less than two years after diagnosis, and many for around a year, although individual experiences vary. Long-term survival is rare but has been reported. Statistics describe large groups and cannot predict a single child’s course, so families should discuss their child’s specific situation with the treating team.

What are the first DIPG symptoms parents notice?

Early DIPG symptoms often involve the eyes and face, such as a new squint, double vision, or a face that looks uneven when smiling. Unsteady walking, clumsiness, slurred speech or difficulty swallowing are also common early signs. These symptoms usually develop and worsen over a few weeks rather than months, which is one reason doctors take a rapidly progressing combination of these signs seriously.

Is a DIPG brain tumor cancer?

Yes. DIPG is a malignant, or cancerous, brain tumor. It is classified as a high-grade glioma, meaning its cells grow quickly and infiltrate surrounding brain tissue. Unlike many cancers, DIPG rarely spreads to other organs; the danger comes from its location within the brainstem, where it disrupts functions essential to life.

Why can’t DIPG be removed with surgery?

The tumor grows diffusely through the pons, mixing with the nerve fibers that control breathing, heart rate, swallowing and movement. There is no clear boundary between tumor and healthy tissue, so surgeons cannot remove the tumor without destroying these functions. Surgery in DIPG is therefore limited to taking a small biopsy sample or relieving fluid pressure when hydrocephalus develops.

Is there a cure for DIPG?

At present, there is no known cure for DIPG. Radiation therapy is the standard treatment and can improve symptoms and extend life, but the tumor usually regrows. Research into targeted drugs, immunotherapy and new drug-delivery methods is active, and clinical trials are available in many regions. Families should be cautious about claims of guaranteed cures from unproven treatments.

Can DIPG occur in adults?

DIPG is overwhelmingly a childhood disease, but diffuse gliomas of the brainstem can occasionally occur in teenagers and adults. In adults, brainstem gliomas tend to behave somewhat differently and may grow more slowly, so diagnosis and treatment are considered individually. The same imaging appearance in an adult does not always carry the same outlook as in a child.

How is diffuse intrinsic pontine glioma diagnosed without a biopsy?

DIPG has a very characteristic appearance on MRI: a diffusely swollen pons with a tumor that has no clear edges and occupies most of the structure. Combined with a short history of typical neurological symptoms in a child of the usual age, this appearance is considered reliable enough that many centers make the diagnosis from imaging alone. Biopsy is increasingly offered to confirm the diagnosis and identify genetic changes that may guide treatment or trial eligibility.

When to see a doctor

Any child who develops new neurological symptoms should be assessed by a doctor promptly, particularly if several symptoms appear together or worsen over days to weeks. Most children with these symptoms will not have a brain tumor, but early evaluation matters.

Seek urgent medical attention, including emergency care if necessary, if a child has:

• Sudden or rapidly worsening double vision, a new squint, or eyes that do not move together.
• Drooping or weakness on one side of the face.
• New unsteadiness, frequent falls, or a noticeable change in the way they walk.
• Weakness, numbness or stiffness in an arm or leg.
• Slurred speech, trouble swallowing, choking on food or drink, or new drooling.
• Persistent headaches, especially those that wake the child or are worse in the morning, particularly when combined with vomiting.
• Unusual drowsiness, confusion, or difficulty waking.
• Changes in breathing pattern, breathing that pauses, or a very slow or irregular heartbeat.
• A seizure, or loss of consciousness.

For a child already diagnosed with DIPG, families are usually given specific guidance on which changes should prompt a call to the care team or a visit to the emergency department. Sudden worsening of swallowing or breathing, new severe headache with vomiting, a marked increase in sleepiness, or a fever while on steroids or during treatment should be reported without delay.