Brain Stem Glioma
Brain stem glioma is a type of tumor that develops in the brainstem, the critical area connecting your brain to your spinal cord. While these tumors most commonly affect children, they can also occur in adults, and their behavior and outlook vary greatly depending on their location and how fast they grow.
Table of contents
- What is brain stem glioma?
- The brainstem and its function
- Types of brain stem glioma
- Symptoms
- How common is brain stem glioma?
- Causes
- Diagnosis
- Treatment options
- Prognosis and survival
What is brain stem glioma?
Brain stem glioma is a general term that refers to all tumors of a certain type that grow in the brainstem[1]. These tumors are part of a larger group called gliomas, which are tumors that develop from glial cells—special cells in the brain and spinal cord that support and protect nerve cells[2].
Most brain stem gliomas are a specific type of tumor called astrocytomas, which form from star-shaped glial cells known as astrocytes[1][4]. These tumors can be graded from I to IV, with the grade indicating how aggressive the tumor is. Lower grade tumors (grade I) tend to grow slowly, while higher grade tumors (grades III and IV) grow much faster and are more aggressive[1].
The brainstem and its function
- Brainstem
- Midbrain
- Pons
- Medulla oblongata
The brainstem is a small but vital part of your brain that connects the base of the brain to the top of the spinal cord, located just above the back of your neck[2]. Although it is small, the brainstem controls many functions that are critical for survival[4].
The brainstem manages essential body functions including breathing, heart rate, blood pressure, digestion, and muscular coordination[1][4]. It also controls the nerves and muscles used in seeing, hearing, walking, talking, and eating[10]. Any of these functions can be affected when a tumor grows in this area.
The brainstem consists of three parts. The midbrain is the uppermost section. The pons is found between the midbrain and the medulla, and most brainstem gliomas arise in this particular part[2][3]. The medulla oblongata is formed by the top of the spinal cord spreading out at the base of the brain[2].
Types of brain stem glioma
Astrocytomas that develop in different regions of the brainstem behave very differently from each other[1]. Brain stem gliomas can be classified based on their growth characteristics and location.
Focal brainstem gliomas grow more slowly and are restricted to one area of the brainstem, usually the midbrain and medulla (the top and bottom segments)[1]. These are typically low grade (grade I) tumors[1]. Focal gliomas are usually easier to treat and have more favorable outcomes[1].
Diffuse intrinsic pontine gliomas, commonly called DIPG, are extremely aggressive grade IV tumors[1]. Although they appear to start in the pons, they can grow throughout the brainstem and neighboring structures[1]. As the name suggests, the tumor cells spread out and invade neighboring tissue[1]. DIPG is the most common type, accounting for approximately 75% to 80% of pediatric brain stem tumors[10]. These tumors tend to be high-grade and very aggressive, making them hard to treat[7].
Gliomas that occur in the midbrain and medulla are usually low grade. However, those that arise in the pons are usually grade IV tumors and typically grow much faster and progress more rapidly[1]. The reason for the very rapid growth of these tumors in this particular area of the brain is still unknown[1].
Symptoms
Symptoms of brain stem glioma depend on several factors, including the tumor’s location, size, and how fast it is growing[4]. Because brainstem gliomas, especially the aggressive types, can grow quickly, symptoms can develop rapidly, over the course of days or weeks[1].
These tumors can impact normal brainstem function, leading to common symptoms that include abnormalities in eye movement, weakness of one side of the face, numbness or weakness of the arms and legs, difficulty with balance, headaches, and nausea[1].
Children with DIPG may present with a classic combination of symptoms, though they may have only one or two at diagnosis. These include problems with eye movement (particularly difficulty moving the eyes outward), long tract signs (which are symptoms caused by damage to nerve pathways that carry signals between the brain and body), and ataxia (difficulty with coordination and balance)[10].
Additional symptoms may include loss of feeling in the face, difficulty speaking clearly, difficulty swallowing, worsening handwriting, double vision, and general weakness[4]. As a brainstem glioma grows, it occupies more space in the rigid skull, which can lead to increased pressure inside the head. This can cause headache, vomiting, nausea, and drowsiness[4]. Headaches resulting from brainstem glioma typically occur in the morning upon waking and get better throughout the day[4].
The tumor can also block the natural flow of cerebrospinal fluid (the fluid that cushions the brain and spinal cord), leading to a condition called hydrocephalus, which causes even higher pressure inside the head[4][10].
How common is brain stem glioma?
Brainstem gliomas usually occur in children, but can occasionally be found in adults[1]. Approximately 300 to 400 pediatric brain stem tumors are diagnosed each year in the United States[10]. Brainstem tumors account for 11% of primary brain tumors in children and adolescents[1]. They represent about 20% of all pediatric primary brain tumors[3].
Most children with DIPG are diagnosed between the ages of 5 and 10 years[10]. In adults, brainstem gliomas constitute less than 2% of all adult gliomas[3]. When they do occur in adults, it tends to be when the patient is in their thirties[26].
Causes
For most patients, the cause of brainstem glioma is unknown[1]. Researchers have not found any direct genetic link, and the cause is still unknown[9].
However, there are a few rare genetic conditions that may increase a patient’s chance of developing brainstem glioma. For example, patients with neurofibromatosis type 1 (NF1) may be more likely to develop brainstem gliomas, among other tumors[1].
Diagnosis
A physician will record a patient’s medical history and conduct a physical examination to establish symptoms[4]. A neurological examination may be performed to evaluate whether the brain, spinal cord, and nerves are working correctly[4]. This exam involves checking vision, hearing, balance, coordination, strength, and reflexes[5].
If a physician suspects a brain tumor or other abnormality, imaging tests are typically ordered[4]. In general, an MRI scan (a test that uses magnets and radio waves to create detailed pictures of the inside of the body) can identify the specific area in the brainstem that the tumor arises from and often is all that is needed to diagnose a brainstem glioma[1]. Magnetic resonance imaging is the preferred imaging test for diagnosing brainstem gliomas[4].
Although historically, many brainstem gliomas were not biopsied, some medical centers now routinely perform biopsies (procedures to remove a small sample of tissue for testing) of brainstem tumors in order to obtain more information about the tumor[1]. A biopsy is sometimes done before treatment begins, especially when surgery isn’t an option for removing the tumor[3]. The tissue that is obtained will confirm the diagnosis and allow analysis of the tumor tissue for specific features, like certain genetic changes, that may inform decisions about treatment options[1].
If you will have surgery to remove your brain tumor, you might not need a biopsy before your surgery[3]. To get the tissue sample during a biopsy, a needle might be used, guided by imaging tests—a procedure called stereotactic needle biopsy[3].
Treatment options
Treatment for brain stem gliomas depends on the type of glioma, the grade of the tumor, the location of the tumor, how far the tumor has grown or spread, whether the tumor can be surgically removed, and the patient’s age and general health[7].
For grade I brainstem gliomas, surgery alone is often curative[1]. If most of the visible tumor cannot be removed with surgery, then treatment with radiation therapy (treatment that uses high-energy rays or particles to destroy cancer cells) can be very effective as an additional treatment[1][7].
However, most brainstem gliomas are grade II-IV and grow more aggressively. Because of their location in the brainstem, which controls many critical functions like breathing, swallowing, and heart rate, treatment for these tumors requires certain considerations[1]. Surgery to remove the tumor is often not possible because it would be too dangerous and would likely do more harm than good[7].
Focal radiotherapy is the cornerstone of treatment for brainstem gliomas and can improve or stabilize the patient’s condition[3][13]. Radiotherapy should be administered to any patient with significant and progressive symptoms[3]. The conventional dose of radiotherapy ranges from 54 to 60 Gy (a measure of radiation dose)[3][13]. Radiation is directed to the area immediately surrounding the tumor and sometimes to the whole brain[7].
Chemotherapy (treatment with drugs that destroy cancer cells) with agents such as temozolomide may benefit some patients with high-grade tumors[3][13]. Chemotherapy may include conventional agents such as temozolomide and carboplatin/vincristine[3]. The effectiveness of chemotherapy at relapse is uncertain, but it may benefit some patients[13]. In some cases, targeted therapy (drugs that target specific genetic changes in tumor cells) may be offered after radiation therapy[7].
Patients should be encouraged to enroll in clinical trials if available[3][13]. In August 2025, the US Food and Drug Administration approved dordaviprone (Modeyso) for the treatment of diffuse midline glioma with a specific genetic change (H3 K27M mutation) in adults and children aged 1 year and older who have progressive disease following prior therapy[13].
Prognosis and survival
The outlook for individuals with brainstem glioma varies greatly depending on the type and grade of the tumor.
Children with focal brainstem gliomas generally have a relatively favorable prognosis, especially when a complete surgical resection can be accomplished. Most children with focal gliomas survive more than 18 months[9]. Focal brainstem gliomas are easier to treat and have a better prognosis than DIPG[7].
In contrast, children with DIPG generally have a poor prognosis[10]. Most children with DIPGs live less than 18 months[9]. DIPG is hard to treat and has a poor prognosis[7].
However, though brainstem gliomas are rarer in adults, the tumors tend to be less aggressive and carry a better prognosis[26]. The current brainstem glioma average survival in adults is approximately 44 to 74 months[26]. This means that many adults diagnosed with brainstem glioma live that much longer following diagnosis.
Response to radiotherapy depends on several variables, such as tumor location and type. Reported survival rates with radiation therapy are better in patients with tumors that grow outward from the brainstem (exophytic tumors)[3][13].
