Ganglioglioma

Overview

Ganglioglioma is a rare tumor that grows in the brain or spinal cord. It's made up of two types of cells found in the nervous system — glial cells and nerve cells. Ganglioglioma is classified as a glioneuronal tumor.

Most gangliogliomas are low grade. That means they are considered noncancerous (benign) and are not aggressive cancers. They grow slowly, are less likely to spread and often can be fully removed with surgery.

When the tumor is completely removed, many people live for many years and may have a typical life expectancy.

Less often, gangliogliomas may have aggressive or high-grade features. These were previously called anaplastic gangliogliomas, which we now know may include different tumor types. That means they grow more quickly and require more intensive treatment. However, high-grade forms are much less common than low-grade tumors.

Gangliogliomas most often occur in the temporal lobe of the brain. This area of the brain is a common site of seizures. Seizures are one of the most common reasons these tumors are discovered. Less often, gangliogliomas can develop in other parts of the brain or in the spinal cord.

This tumor is seen most often in children, adolescents and young adults, although it can occur at any age. Ganglioglioma accounts for a small percentage of all brain tumors.

Types

Gangliogliomas are grouped by features seen under the microscope and other genetic characteristics. Gangliogliomas are classified by the World Health Organization as low grade (WHO grade 1).

• Ganglioglioma (WHO grade 1). This is the most common type of ganglioglioma.

  Low-grade tumors grow slowly. They usually stay in one area of the brain or spinal cord. In many cases, surgery can remove the tumor completely. When that happens, long-term survival rates are high.

  Gangliogliomas are often linked to seizures, especially when the tumors grow in the temporal lobe of the brain.

  Very rarely gangliogliomas can develop high-grade or aggressive features, which is most often at time of progression or recurrence. High-grade tumors grow more quickly and are more likely to return after treatment. They often require additional treatment beyond surgery, such as radiation therapy or chemotherapy.

• Desmoplastic infantile ganglioglioma (DIG). Desmoplastic infantile ganglioglioma is a rare type that mainly affects infants and very young children.

  Desmoplastic infantile gangliogliomas most often occur in the cerebral hemispheres. Rarely, they have been reported in other areas of the brain. This includes the posterior cranial fossa, which contains the cerebellum.

  These tumors can be large at the time they are found. Even so, they are usually low-grade, slow-growing tumors. With surgery, many children have good outcomes.

Is anaplastic ganglioglioma still a grade 3 tumor?

Before 2021, some tumors were called anaplastic ganglioglioma and labeled WHO grade 3. Doctors made this diagnosis mostly by looking at the tumor under a microscope. If the tumor looked like a ganglioglioma but also showed more-aggressive features, it was called anaplastic, which meant higher grade.

At the time, experts believed these tumors were all the same type — just a more aggressive form of ganglioglioma.

What changed?

As genetic testing improved, researchers began studying these tumors more closely. This testing, called molecular testing, looks at the tumor's genes. When experts tested tumors that had been labeled anaplastic ganglioglioma, they found that most of them did not share the same genetic features.

Instead, many of these tumors matched the genetic patterns of other known tumor types, including:

• Pleomorphic xanthoastrocytoma (PXA).
• Glioblastoma, IDH-wildtype.
• Diffuse pediatric-type high-grade glioma.
• IDH-mutant astrocytoma.
• Other glioneuronal tumors.

This meant that what had been grouped together as one diagnosis was actually a mix of different tumor types that only looked alike under the microscope.

What does this mean?

Today, tumors are classified using information about how they look under a microscope and their genetic and molecular features.

Gangliogliomas are usually described in one of two ways:

• Central nervous system (CNS) WHO grade 1 (low-grade).
• Higher grade tumors that fit into other WHO-defined categories.

Because these tumors turned out to be biologically different diseases, the 2021 World Health Organization (WHO) Classification of Tumors of the Central Nervous System removed anaplastic ganglioglioma as an official diagnosis. There is no longer a recognized WHO grade 3 ganglioglioma category.

Pilocytic features

Some people may see the words pilocytic features in their pathology reports. A pathology report is the written summary a specialist creates after studying the tumor under a microscope.

Pilocytic features means that some parts of the tumor look similar to a tumor called pilocytic astrocytoma. It describes how the cells appear under the microscope. It does not mean the tumor is a different condition. Pilocytic astrocytoma and ganglioglioma are different tumor types, even though they can look similar in some ways.

Symptoms

Symptoms of ganglioglioma depend on where the tumor is located in the brain or spinal cord. Common signs and symptoms include:

• Seizures. Seizures are the most common symptom, especially when the tumor is in the temporal lobe. For some people, seizures may have been happening for months or even years before the tumor is found.
• Headaches. Headaches can occur, especially if the tumor causes pressure inside the skull. Headaches may be more frequent in the morning or linked to nausea.
• Changes in thinking or behavior. If the tumor affects areas of the brain involved in memory, speech or mood, it may cause memory problems, trouble speaking, or changes in personality or behavior.
• Weakness or balance problems. Tumors in certain parts of the brain may cause weakness on one side of the body, balance problems or trouble with coordination. If the tumor is in the spinal cord, it may cause weakness, numbness or difficulty walking.
• Symptoms in infants and young children. In infants, symptoms may look different. Signs can include an enlarged head size, vomiting, irritability or delays in development.

When to seek care

You should contact a healthcare professional if you or your child has:

• New or unexplained seizures.
• Seizures that are becoming more frequent.
• Ongoing headaches that are getting worse.
• Changes in behavior, memory or speech.
• Weakness, numbness or balance problems.

These symptoms do not always mean there is a tumor. Many other conditions can cause similar symptoms. However, ongoing or worsening symptoms should be checked by a healthcare professional.

Causes

The exact cause of ganglioglioma is often unknown.

Most gangliogliomas develop because of changes in certain genes that control how cells grow and divide. These changes only happen inside the tumor cells. They are not usually passed down in families.

Many gangliogliomas have changes that affect a cell growth pathway called the RAS-MAPK pathway. Changes in a gene called BRAF are common. These genetic changes help explain how the tumor forms, but they do not usually mean the condition is inherited.

In most people, ganglioglioma is not caused by anything a parent did or did not do. It is not linked to diet, lifestyle or routine activities.

Rarely, brain tumors can occur in people with certain genetic conditions, but ganglioglioma is usually not related to a genetic condition.

Risk factors

There are no known risk factors for ganglioglioma.

Ganglioglioma is most often diagnosed in children, teens and young adults. It's less common in adults.

Most people who develop this tumor do not have any known medical condition that raises their risk.

Prevention

There is no known way to prevent ganglioglioma.

Ganglioglioma usually develops without a known trigger. Because of this, there are no screening tests or preventive steps recommended for the general population.

Diagnosis

Ganglioglioma is usually found after imaging tests are done to look for the cause of symptoms, most often seizures or headaches.

Most people first see their regular healthcare professional to determine what may be causing these symptoms. The evaluation usually begins with a review of medical history and a physical exam. A neurological exam also may be performed to assess strength, balance, reflexes, memory and speech.

If symptoms suggest an issue in the brain or spinal cord, you may have imaging tests. In many cases, the person is referred to a neurologist or neurosurgeon for more testing.

Imaging tests

Magnetic resonance imaging (MRI) is the main test used to look for a ganglioglioma. On MRI, these tumors often appear as a well-defined mass. Many have both solid fluid-filled (cystic) parts. Small areas of calcium buildup, called calcifications, also may be seen.

Low-grade tumors usually cause little swelling in the nearby brain tissue. High-grade tumors are more likely to cause more swelling.

Gangliogliomas may appear more clearly on MRI after contrast is injected. The contrast is given through a small needle placed in a vein in your hand or arm (IV) during the scan. Your care team should let you know ahead of time if contrast will be used.

Imaging can strongly suggest ganglioglioma, but it cannot confirm the diagnosis on its own.

Surgery and biopsy

To confirm the diagnosis, tissue must be looked at under a microscope. This usually happens during surgery to remove the tumor. This process is called a biopsy.

Under the microscope, doctors look for unusual looking nerve cells and glial cells. Finding both cell types helps confirm the diagnosis.

The tumor may be tested for gene changes. A change in a gene called BRAF is common in ganglioglioma. Finding this change can help the care team confirm the type of tumor.

Other conditions that may look similar

Several other conditions can look similar to ganglioglioma on imaging or under the microscope.

Dysembryoplastic neuroepithelial tumor (DNET) is another low-grade tumor that is commonly linked to seizures. Like ganglioglioma, it often occurs in the temporal lobe and has a generally positive outlook. A biopsy or surgery helps distinguish between the two.

Gangliocytoma is closely related to ganglioglioma. Gangliocytoma is made mostly of nerve cells and has little or no glial cell tumor tissue.

A ganglion cyst is completely different. It is a fluid-filled sac that usually forms near joints, such as the wrist. It does not form in the brain and is not a brain tumor.

Careful review of imaging tests and the tumor tissue helps the care team make the correct diagnosis.

Treatment

Treatment for ganglioglioma depends on the tumor's location and whether it can be completely removed with surgery.

Surgery

Surgery is the main treatment for ganglioglioma, as long as it can be done safely without damaging important areas of the brain responsible for speech, memory and movement.

The goal of surgery is to remove as much of the tumor as safely possible. In many cases, the tumor can be completely removed. For most people with a low-grade ganglioglioma, surgery may be the only treatment needed.

Chemotherapy and radiation therapy are not generally needed when the tumor has been fully removed.

Surgery also can help reduce or stop seizures in people whose tumors are linked to epilepsy.

Monitoring after surgery

If the tumor is fully removed and is low grade, the care team may recommend regular brain MRI scans to make sure the tumor has not grown back, instead of starting additional treatment right away.

Radiation therapy and chemotherapy

Additional treatment may be recommended if:

• The tumor cannot be completely removed.
• The tumor returns.
• The tumor is high grade.

High-grade gangliogliomas that very rarely occur with tumor recurrence or progression often require radiation therapy and sometimes chemotherapy after surgery.

Radiation therapy is used carefully in children because of potential long-term side effects.

For low-grade tumors that cannot be fully removed, the care team may recommend close monitoring with regular MRI scans before starting additional treatment. Decisions about radiation or chemotherapy are made carefully. They are based on whether the tumor grows, changes over time or returns after surgery.

Targeted therapy

Some gangliogliomas have specific genetic changes, such as changes in the BRAF gene.

In certain cases, targeted therapies may be used. These medicines are designed to block the effect of specific gene changes that help the tumor grow.

Targeted therapy may be considered if the tumor returns or cannot be fully removed. These treatments are still being studied and are not needed for most people with low-grade tumors with surgical treatment.

Treatment in children vs. adults

Treatment approaches are similar in children and adults. In children, the care team tries to limit radiation when possible because the brain is still developing. This helps reduce the risk of long-term side effects.

The long-term outlook depends on the tumor's grade and whether it can be completely removed.

The outlook for ganglioglioma depends mainly on the tumor's grade and whether it can be completely removed with surgery, and if the tumor comes back after initial treatment.

Low-grade ganglioglioma

Most gangliogliomas are low grade. Removing the entire tumor during surgery is one of the most important factors linked to a good outcome. The risk that ganglioglioma will grow back is much lower when the tumor is fully removed.

In most studies, long-term survival for gangliogliomas is well above 80% to 90%, especially when the tumor can be completely removed.

Many people with completely removed low-grade tumors live for many years and may have a typical life expectancy.

Low-grade gangliogliomas can rarely return, especially if the tumor could not be completely removed. The risk of the ganglioglioma coming back is much lower when surgery removes the entire tumor. If the tumor does grow back, additional treatment can often help control it.

What affects prognosis

Prognosis can depend on:

• If the tumor comes back after initial surgery.
• Whether the tumor can be completely removed.
• Where the tumor is located.
• The person's age at diagnosis.

Removing the entire tumor during surgery is one of the most important factors linked to a good outcome. The ganglioglioma recurrence rate is much lower when the tumor is fully removed.

Tumors described as having pilocytic features usually behave like other low-grade gangliogliomas. When treated appropriately, they generally have a good outlook.

Lifestyle and home remedies

People with ganglioglioma can take steps to support their health during and after treatment.

• Follow the treatment plan. Take prescribed medications as directed and attend all follow-up appointments. Regular MRI scans help monitor for recurrence.
• Manage seizures safely. If seizures are part of the condition, follow the care team's guidance about seizure medications and safety precautions. Avoid activities that could be dangerous if a seizure occurs, such as swimming alone or climbing heights.
• Rest and recover after surgery. It can take time to regain strength after brain surgery. Getting enough rest and gradually returning to your usual activities can support recovery.
• Seek emotional support. A brain tumor diagnosis can be stressful. Counseling, support groups or talking with a trusted professional may help both adults and parents of affected children cope with anxiety and uncertainty.
• Make adjustments for school and work. Children may need temporary academic adjustments. Adults may need time off work or modified duties during recovery.

Coping and support

A ganglioglioma diagnosis can be overwhelming and frightening. It can make you feel like you have little control over your health. But you can take steps to cope with the shock and grief that may come after your diagnosis.

Consider trying to:

• Learn more about gangliogliomas. Ask your healthcare team about your specific type of brain tumor, including your treatment options. As you learn more about brain tumors, you may become more confident in making treatment decisions.
• Stay in touch with friends and family. Keeping your close relationships strong will help you cope with your brain tumor. Friends and family can provide the practical support you'll need, such as helping take care of your home if you're in the hospital. And they can serve as emotional support when you feel overwhelmed by cancer.
• Find someone to talk with. Find a good listener who is willing to listen to you talk about your hopes and fears. This may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or cancer support group also may be helpful. Ask your healthcare team about support groups in your area. Or connect with others online through groups, such as the National Brain Tumor Society and others.

For family members and friends

Supporting someone with a ganglioglioma can feel overwhelming. You may feel unsure how to help or what to say. Consider learning about the condition, attending appointments if invited and offering practical help with daily tasks. Listening without trying to fix everything also can be meaningful.

It also is important to take care of your own well-being. Consider seeking support from a counselor, support group or trusted friend.

Preparing for an appointment

See your usual healthcare professional if you have any signs or symptoms that worry you. If you're diagnosed with a ganglioglioma, you may be referred to specialists, such as:

• Doctors who specialize in brain disorders, who are called neurologists.
• Doctors who treat cancer with medicine, who are called medical oncologists.
• Doctors who use radiation to treat cancer, who are called radiation oncologists.
• Doctors who specialize in nervous system cancers, who are called neuro-oncologists.
• Surgeons who operate on the brain and nervous system, who are called neurosurgeons.
• Rehabilitation specialists.

Brain tumor treatment can be complex. Few hospitals are used to caring for a lot of people with brain tumors. If you don't feel comfortable with the care at your local facility, consider seeking a second opinion at a more experienced cancer center. Ask your healthcare professional for a referral.

It's a good idea to be prepared for your appointment. Here's some information to help you get ready.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medications, vitamins or supplements that you're taking.
• Consider taking a family member or friend along. Sometimes it can be difficult to remember all the information provided during an appointment. Someone who goes with you may remember something that you missed or forgot. This person can be your advocate and help you understand the information you receive from your healthcare team.
• Write down questions to ask your healthcare professional. A written list of questions and concerns is helpful when you're feeling overwhelmed. There's a lot of information to process and consider when you're dealing with a serious illness. It's easy to forget the questions you wanted to ask.

Your time with your healthcare professional is limited, so preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. For a brain tumor such as ganglioglioma, some basic questions to ask include:

• What type of brain tumor do I have?
• Where is my brain tumor located?
• How large is my tumor?
• How aggressive is my brain tumor?
• Is my glioma cancerous?
• Will I need additional tests?
• What are my treatment options?
• Can any treatments cure my glioma?
• What are the benefits and risks of each treatment?
• Is there one treatment you feel is best for me?
• Is there a clinical trial available to treat my type of ganglioglioma? Is it appropriate for me?
• How will treatment affect my daily activities, such as walking, talking and speaking?
• Should I see a specialist? What will that cost, and will my insurance cover it?
• Are there brochures or other printed material that I can take with me? What websites do you recommend?
• How often should I have checkups?

Note the three questions that are most important to you so that you can be sure to get those answered if the time is limited. In addition to the questions that you've prepared to ask, don't hesitate to ask other questions that occur to you.

What to expect from your doctor

Your healthcare professional is likely to ask you a number of questions. Being ready to answer them may allow time later to cover other points you want to address. They may ask:

• When did you first begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?