Diagnosis
Diagnosing a brainstem tumor begins with learning about symptoms and doing a physical exam. A neurological exam is used to check balance, eye motion, strength, coordination and swallowing. These findings help the care team understand which parts of the brainstem may be affected.
Imaging tests are then used to look closely at the brainstem. In some cases, a small sample of tissue or cerebrospinal fluid may be taken to learn more about the tumor's cells to establish a diagnosis.
Imaging tests
Magnetic resonance imaging (MRI). A brain MRI is the main test used to diagnose a brainstem tumor. It creates detailed pictures of the brainstem and can show whether a growth is present, where it is located, and how it affects nearby structures. MRI scans can show features that help identify:
- The expected type of tumor.
- How much of the brainstem is involved.
- Whether the growth stays in one area or spreads throughout other areas.
MRI with and without contrast can help identify common tumor types, including diffuse midline glioma (DMG) and other gliomas that can form in the brainstem.
MRI also can show whether the tumor stays in one area or spreads through brainstem tissue, which helps guide the next steps in diagnosis.
A mass that shows on brainstem MRI means there is an area that looks different from the surrounding tissue. This may be a tumor or another type of lesion. MRI helps show the size and position of the mass and how it affects nearby areas.
Some changes seen on brainstem MRI scans may be caused by conditions other than a tumor, such as inflammation, cavernous malformations, or other types of lesions including inflammatory or demyelinating conditions such as multiple sclerosis. Imaging tests help the care team understand the cause and guide other testing.
Other imaging. Depending on the situation, the care team may use additional imaging to better understand the growth or to rule out other conditions. These may include brain CT scans or specialized MRI techniques. These tests help confirm the tumor's position and its effect on surrounding areas.
Biopsy
In some cases, a small sample of tissue is taken with a needle to study the tumor's cells. This is called a needle biopsy. Modern techniques allow biopsies to be performed with high accuracy and a low rate of lasting side effects.
A biopsy is most helpful when MRI results are unclear or when several tumor types are possible based on imaging alone.
Lumbar puncture
In some situations, a lumbar puncture may be done to look at the spinal fluid for clues about the tumor. The fluid can be checked for cells that have moved from the tumor or for genetic changes that point to a certain type of tumor. This information can help confirm what type of tumor you have and help the care team plan next steps.
How results are used
After imaging and biopsy results are collected, the care team looks at the tumor's location, its pattern of growth and the features of the cells. These details help identify the tumor type and guide decisions in later steps of care.
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Treatment
Treatment for a brainstem tumor depends on the tumor's type, size and location. The main treatments for brainstem tumors include:
- Surgery.
- Biopsy.
- Radiation therapy.
- Chemotherapy.
- Targeted therapy.
The goal of cancer treatment is to manage the tumor's growth and to help protect movement, breathing, swallowing and other functions guided by the brainstem.
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Surgery. Brain tumor surgery may be used when a tumor is in a spot that can be reached safely. This is more common with tumors that grow in one area, such as some low-grade gliomas. Growths that reach open fluid-filled spaces around the brainstem can sometimes be easier to remove.
Many brainstem tumors cannot be fully removed because they grow near areas that control important functions such as movement, breathing and swallowing. In these cases, surgery may be limited to removing part of the growth or reducing pressure in nearby spaces.
- Biopsy. A biopsy is a small sample of the tumor taken with a needle. While a biopsy helps confirm the tumor's type, it also guides treatment choices by showing gene changes or other features that can shape the care plan. Newer methods allow the sample to be taken safely with a low chance of lasting problems.
- Radiation therapy. Radiation therapy uses focused energy beams to slow or stop tumor growth. It is often used for diffuse midline glioma and other tumors that cannot be removed with surgery. Radiation may improve symptoms caused by pressure on nearby structures. Prior radiation can raise the risk of delayed injury to brain or brainstem tissue. This means damage caused by radiation that may not appear until months or years after treatment ends.
- Chemotherapy. Chemotherapy may be used to target fast-growing tumors or to help manage growth in tumors that return after earlier treatment. Different medicines may be used based on the type of tumor and how quickly it grows.
- Targeted therapy. Some tumors have gene changes that affect how tumor cells grow. Targeted therapy uses medicines designed to block these growth signals inside the tumor cells. These treatments are used when specific gene changes, such as certain BRAF gene changes, are found in the tumor. Dordaviprone is a newer medicine approved for the treatment of diffuse midline gliomas. Research continues to study how targeted therapy may help children and adults with brainstem gliomas.
- Immunotherapy. Researchers are studying whether treatments that help the immune system recognize tumor cells, such as chimeric antigen receptor (CAR)-T cell therapy-targeting proteins such as GD2, may support care for diffuse midline gliomas. Early studies in children and young adults have shown promising responses in some cases.
- Supportive care. Treatments also may focus on easing symptoms caused by pressure on nerve pathways in the brainstem. This may include care to support swallowing, breathing, movement or fluid balance when needed.
Clinical trials and emerging treatments
Clinical trials are research studies that test new ways to find, treat or understand brainstem tumors. These studies are important because many brainstem tumors, especially diffuse midline gliomas, are difficult to treat with current options.
Treatments that target gene changes
Researchers are studying treatments that act on gene changes found in some low-grade gliomas and diffuse midline gliomas. These studies may look at medicines that act on growth signals inside the tumor or medicines matched to specific gene changes, including the BRAF gene.
Some studies are testing medicines that block signals inside tumor cells that tell them to grow. Early research shows these medicines may slow growth in some low-grade gliomas, but more studies are needed to understand how well they work in brainstem tumors.
New ways to deliver medicine
Other trials are testing new ways to deliver medicine directly to the brainstem. These approaches aim to reach the tumor more effectively while limiting effects on nearby areas that guide movement, breathing and swallowing.
Advances in imaging, biopsy and supportive care
Trials also are studying new imaging tools, biopsy methods and supportive treatments. These studies help the care team understand how brainstem tumors grow and how they respond to different therapies.
Ongoing research continues to explore the genetic and molecular features of brainstem tumors to guide new treatment options.
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Prognosis
The outlook for a brainstem tumor depends greatly on the tumor's type, where it is located and how it grows. Some tumors grow slowly and may stay in one area for a long time. Others grow quickly and are harder to control because they spread through brainstem tissue.
Life expectancy also varies based on these factors. There is no single cure for all brainstem tumors, and outcomes depend on how the tumor behaves over time.
Tumors that grow quickly
Tumors such as diffuse midline glioma tend to grow quickly and are harder to control. These tumors often spread through the pons and surrounding areas, which limits the options for removing or slowing the growth. This pattern can lead to a shorter survival.
Tumors that grow slowly
Low-grade gliomas usually grow more slowly. These tumors may stay in one spot and can sometimes be managed for long periods with treatment or observation. Pilocytic astrocytoma, pilomyxoid astrocytoma, fibrillary astrocytoma and ganglioglioma belong to this group.
Other factors
The tumor's size and position in the midbrain, pons or medulla can affect the outlook because these areas guide important body functions. Age also plays a role. Children are more likely to have tumors that begin in the pons, while adults have a wider mix of tumor positions.
Prognosis is different for each person. But understanding the type of brainstem tumor and how it grows is an important first step in planning care.
Preparing for your appointment
If you have symptoms that worry you, make an appointment with a doctor or other healthcare professional. If you have a brainstem tumor, you'll likely be referred to specialists, such as:
- Doctors who specialize in brain conditions, called neurologists.
- Doctors who treat cancer with medicine, called medical oncologists.
- Doctors who use radiation to treat cancer, called radiation oncologists.
- Doctors who specialize in nervous system cancers, called neuro-oncologists.
- Surgeons who operate on the brain and nervous system, called neurosurgeons.
- Rehabilitation specialists.
Here's some information to help you get ready for your appointment.
What you can do
- Be aware of anything you need to do before your appointment. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as change your diet.
- Write down any symptoms you've been experiencing and how long you've had them.
- List your key medical information, including all conditions you have and the names of any medicines you're taking. Include prescription medicines and medicines you can buy without a prescription and the doses.
- Take a family member or friend with you. Sometimes it can be difficult to remember all of the information you get during an appointment. Someone who goes with you may remember something that you missed or forgot.
- Write down questions to ask your healthcare professional.
Questions to ask at your first appointment include:
- What may be causing my symptoms?
- Are there any other possible causes?
- What kinds of tests do I need? Do these tests require any special preparation?
- What do you recommend for the next steps in determining my diagnosis and treatment?
- Should I see a specialist?
Questions to ask an oncologist or a neurologist include:
- Do I have a brainstem tumor?
- How will the brainstem tumor grow over time?
- Where is the brainstem tumor located?
- How large is the brainstem tumor?
- What might happen because of the brainstem tumor?
- What are the goals of my treatment?
- Is surgery a treatment option? What are the risks?
- Is radiation therapy a treatment option? What are the risks?
- Will I need chemotherapy?
- What treatment approach do you recommend?
- If the first treatment doesn't work, what will we try next?
- What is the prognosis for my condition?
- Do I need a second opinion?
- Is there a clinical trial available for people with a brainstem tumor? Is it right for me?
In addition to the questions that you've prepared, don't hesitate to ask any other questions that may come up during your appointment.
What to expect from your doctor
Be prepared to answer questions about your symptoms and your health history. Questions may include:
- What are your symptoms?
- When did you first notice these symptoms?
- Have your symptoms gotten worse over time?
- If you have pain, where does the pain seem to start?
- Does the pain spread to other parts of your body?
- Have you participated in any activities that might explain the pain, such as a new exercise or a long stretch of gardening?
- Have you experienced any weakness or numbness in your legs?
- Have you had any difficulty walking?
- Have you had any changes in your bladder or bowel function?
- Have you been diagnosed with any other medical conditions?
- Are you currently taking any medicines, including prescription medicines and medicines that you can get without a prescription?
- Do you have any family history of noncancerous or cancerous tumors?
Feb. 06, 2026