Central nervous system (CNS) lymphoma is a type of lymphoma. Lymphoma is cancer that affects the lymphatic system. The lymphatic system is made up of organs, glands, tubelike vessels and clusters of cells called lymph nodes. It is part of the body's immune system.

There are many types of lymphoma. Lymphomas are often grouped into two main types: Hodgkin lymphoma and non-Hodgkin lymphoma. Most CNS lymphomas are non-Hodgkin lymphomas.

CNS lymphoma affects the central nervous system, which includes the brain, the spinal cord and the fluid that surrounds them. It also can affect the eyes. Although CNS lymphoma can appear in the brain, it is different from most brain tumors because it starts in immune cells called lymphocytes. These cells usually help fight infection. In CNS lymphoma, they start to grow out of control in the central nervous system. As the cancer cells grow, they can form one or more tumors, sometimes called masses.

CNS lymphoma is a serious and potentially life-threatening illness, but there are treatment options. Your outcome depends on factors such as your overall health, how much of the central nervous system is affected and how well the treatment destroys the cancer.

Types

There are two main types of central nervous system (CNS) lymphoma. This cancer is classified based on where it started.

Primary CNS lymphoma

Primary CNS lymphoma (PCNSL) starts in the central nervous system. This includes the brain, the spinal cord and the fluid that surrounds them. It also can affect the eyes.

Most PCNSLs are diffuse large B-cell lymphomas. They begin in lymphocytes called B cells. This cancer affects parts of the nervous system that control thinking, movement and vision, so symptoms often include changes in how the brain works.

Secondary CNS lymphoma

Secondary CNS lymphoma (SCNSL) begins in another part of the body, such as the lymph nodes or other organs. SCNSL can spread to the brain, the spinal cord or the fluid around them. It also can spread to the eyes.

Symptoms of central nervous system (CNS) lymphoma can vary from person to person. They often depend on where the cancer is located within the central nervous system.

Some common symptoms are:

• Headaches that don't go away or get worse over time.
• Nausea and vomiting.
• Changes in thinking, memory or concentration.
• Changes in personality or behavior.
• Weakness or numbness in part of the body.
• Trouble with balance or walking.
• Seizures.
• Vision problems, such as blurred vision.

Some symptoms develop gradually, while others may appear suddenly or get worse quickly.

The exact cause of central nervous system (CNS) lymphoma is not known. It happens when changes occur in certain immune cells called lymphocytes. These changes cause the cells to grow out of control and form cancer.

In primary CNS lymphoma, the cancer begins in the brain, the spinal cord or the fluid around them. It also can begin in the eyes. In secondary CNS lymphoma, the cancer starts elsewhere in the body and later spreads to the central nervous system.

Researchers don't know why lymphoma develops in the central nervous system in some people. The disease may be linked to changes in the immune system that affect how lymphocytes grow and function.

Factors that can increase the risk of developing central nervous system (CNS) lymphoma include:

• Older age. Primary CNS lymphoma is more common in older adults. It occurs most often in people in their 60s and 70s.
• A weakened immune system. CNS lymphoma is more likely if the immune system is not working properly. People with weakened immune systems include those who take medicine to control the immune system, such as after an organ transplant. Some health conditions, such as HIV/AIDS, also can weaken the immune system.
• Epstein-Barr virus (EBV). EBV infection has been linked to CNS lymphoma, especially in people with weakened immune systems.

If you have lymphoma in another part of the body, the risk of it spreading to the CNS depends partly on the type of lymphoma. Some aggressive types are more likely to spread to the CNS.

Central nervous system (CNS) lymphoma and its treatment can sometimes cause complications, either during treatment or afterward.

Possible complications include:

• Increased pressure in the brain. Tumors or swelling can raise pressure inside the skull. This may lead to worsening headaches, nausea, vomiting or changes in alertness.
• Lasting problems with movement, speech or vision. Damage to the brain, spinal cord or eyes can cause ongoing changes, even after treatment ends.
• Infections. Some treatments can weaken the immune system, which increases the risk of infections.
• Changes in memory or thinking. Some treatments, especially those that affect the brain, can cause changes in thinking, memory or focus, either for a short time or long term.

Not everyone with CNS lymphoma has these complications. Your healthcare team watches for any problems and helps manage them if they happen.

Diagnosing central nervous system (CNS) lymphoma often involves several steps. CNS lymphoma can look like other brain conditions on scans, including gliomas, brain metastases and infections. In people with weak immune systems, an infection called toxoplasmosis also can cause brain lesions that may look similar to CNS lymphoma. Because of this, several tests may be needed to confirm the diagnosis.

To find out if someone has CNS lymphoma, a healthcare professional may suggest the following:

• Neurological exam. A neurological exam tests vision, balance, coordination, strength, reflexes and thinking skills. Any changes can help show which part of the nervous system might be involved.
• Imaging tests. Imaging tests help create detailed pictures of the brain and spinal cord. MRI is often used. Sometimes a CT scan may be done instead. Additional imaging tests may be done to check for lymphoma in other parts of the body.
• Biopsy. A biopsy removes a small piece of tissue from the affected area. The sample is checked in a lab for cancer cells. A biopsy is usually needed to confirm CNS lymphoma.
• Spinal fluid tests. A lumbar puncture is a procedure to collect fluid from around the spinal cord. A lumbar puncture, also called a spinal tap, is done using a needle. A healthcare professional inserts the needle between two bones in the lower back and draws out some of the fluid that surrounds the brain and spinal cord. This fluid is called cerebrospinal fluid. The fluid goes to a lab where it's tested for cancer cells.
• Eye exam. If there are eye symptoms, an eye specialist may perform a full exam. This can include using a microscope with a bright light, called a slit-lamp eye exam, to check for signs of lymphoma.

On MRI or CT scans, CNS lymphoma usually looks like a spot that gets brighter after contrast is used. This is called enhancement. Sometimes the outer edge looks brighter than the center, creating a ring shape called ring enhancement. These findings can suggest lymphoma, but imaging alone cannot confirm the diagnosis. A biopsy is usually needed.

Your care team also may do other tests to see if lymphoma is in other parts of the body. These tests help show if the CNS lymphoma started in the brain or spread from somewhere else, which guides treatment choices.

Staging

Many cancers use stages, such as stage 1, 2, 3 or 4, to describe how far the cancer has spread. CNS lymphoma is often described differently. Instead of focusing on numbered stages, healthcare professionals focus on where the lymphoma is found and whether it is limited to the nervous system or also involves other parts of the body.

The healthcare team uses tests to learn:

• Where the lymphoma is located, such as the brain, the spinal cord or the fluid surrounding them, and whether it involves the eyes.
• Whether the lymphoma started in the central nervous system or spread there from another part of the body.
• How much the lymphoma has spread within the central nervous system.

To do this, your healthcare team may use tests to check:

• The brain and spinal cord.
• The eyes.
• The fluid around the brain and spinal cord, called cerebrospinal fluid.
• Other parts of the body, such as the lymph nodes, chest, abdomen, testicles or bone marrow.

These tests help your healthcare team understand the extent of CNS lymphoma and plan treatment. In some cases, healthcare professionals also use the Ann Arbor staging system to describe lymphoma. In that system, primary CNS lymphoma may be described as stage 1E. This means lymphoma is in one area outside the lymph nodes.

Treatment for central nervous system (CNS) lymphoma usually begins with chemotherapy. Other treatments include immunotherapy, targeted therapy, corticosteroids, radiation therapy and chimeric antigen receptor (CAR)-T cell therapy. This also is called CAR-T cell therapy. Sometimes healthcare teams use high-dose chemotherapy followed by a bone marrow transplant, also called a bone marrow stem cell transplant to treat this cancer.

Treatment depends on the type of CNS lymphoma, your overall health, your age and how much of the central nervous system is involved. The goal of treatment is to control the cancer, ease symptoms and protect brain function.

Chemotherapy

Chemotherapy treats cancer with strong medicines. There are many chemotherapy medicines. Most chemotherapy medicines are given through a vein. Some come in pill form.

Chemotherapy is the main treatment for many people with CNS lymphoma. High doses of certain chemotherapy medicines may be used because they can reach the brain and spinal cord.

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. The energy can come from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around you. The machine directs radiation to precise points in your body.

Radiation therapy may be used alone or after chemotherapy to treat CNS lymphoma. Because radiation to the brain can affect memory and thinking, healthcare professionals carefully weigh the benefits and risks before recommending this treatment.

Bone marrow transplant

Sometimes healthcare professionals recommend high-dose chemotherapy followed by a bone marrow transplant, also called a bone marrow stem cell transplant, to treat CNS lymphoma. This approach may be used after the lymphoma responds to initial treatment or if the lymphoma comes back.

A bone marrow transplant replaces blood-forming cells that are damaged by high doses of chemotherapy. This helps the body recover and allows healthcare professionals to use intensive chemotherapy to treat the lymphoma.

Immunotherapy and targeted therapy

Immunotherapy and targeted therapy use medicines that help the body find and attack cancer cells. Some help the immune system recognize cancer. Others block signals that cancer cells need to grow.

These treatments may be used to treat CNS lymphoma in some cases. They may be given with chemotherapy or used if the lymphoma returns or does not respond to other therapies.

Steroids

Corticosteroids may be used to reduce swelling in the brain and ease symptoms. In some cases, these medicines may be delayed until after a biopsy is done because they can affect test results.

CAR-T cell therapy

Chimeric antigen receptor (CAR)-T cell therapy trains immune system cells, called T cells, to fight cancer. This treatment begins with removing some white blood cells, including T cells, from the blood.

The cells are sent to a lab. In the lab, the cells are treated so that they make special receptors. The receptors help the cells recognize a marker on the surface of cancer cells. Then the cells go back into the body. They can find and destroy cancer cells.

CAR-T cell therapy may be an option for some people with primary CNS lymphoma that has not improved with other treatments, known as refractory disease. It also may be used if the lymphoma returns after treatment, which is called relapsed disease.

HIV treatment

If CNS lymphoma is related to HIV infection, treatment of HIV with antiretroviral therapy is an important part of care. These medicines help strengthen the immune system and improve treatment outcomes.

Finding out you have central nervous system (CNS) lymphoma can be hard. Give yourself time to understand your condition and the treatments available. Ask your healthcare team any questions you have and make notes about important details.

Your family and friends can support you during treatment. Talking with others who have cancer also may bring comfort. Support groups let you share your experiences and learn from people facing similar challenges. Find support online through Mayo Clinic Connect, a community where you can connect with others for support, practical information and answers to everyday questions.

If you feel overwhelmed, talk with your care team. Your team can help you find counselors, social workers or other support.

If you notice symptoms that worry you, make an appointment with your regular healthcare professional. If your tests point to central nervous system (CNS) lymphoma, you might be sent to see a specialist, such as a neurologist or a hematologist.

Appointments can be brief, and there may be a lot of information to cover. Preparing ahead of time can help you make the most of your visit.

What you can do

• List any symptoms you have, when they began and if they have changed over time.
• Note any important personal details, such as major stresses, recent illnesses or changes in your health.
• Make a list of all medicines you take, including prescription medicines, medicines you can buy without a prescription, vitamins and supplements, and the doses.
• Bring any copies of your medical records, scans or test results if you have them.
• Consider bringing a family member or friend. Someone who comes with you may help remember information.
• Write down any questions you want to ask your healthcare professional.

Questions to ask may include:

• What could be causing my symptoms?
• What tests do I need?
• Is my condition likely to be temporary or long term?
• What treatment options are available?
• What side effects might the treatment have?
• What should I expect going forward?

What to expect from your doctor

Your healthcare professional likely will ask about your symptoms and health history, such as:

• When did your symptoms begin?
• Have your symptoms changed over time?
• Do you have headaches, vision changes or issues with balance?
• Have you had cancer or any concerns with your immune system?
• What medicines do you take?

Your answers can help guide testing and treatment decisions.

Survival rates describe how many people with central nervous system (CNS) lymphoma are alive after a certain amount of time, often five years after diagnosis.

Primary CNS lymphoma survival rates vary by age. Younger people tend to have higher survival rates than adults. The five-year survival rates by age are:

• Ages 0 to 14: 86%.
• Ages 15 to 39: 61%.
• Age 40 and older: 38%.

People with primary CNS lymphoma tend to have better outcomes than do those with secondary CNS lymphoma. This is because secondary CNS lymphoma usually develops after lymphoma has already affected other parts of the body.

CNS lymphoma may return after treatment. When relapse happens, it often occurs within the first few years after diagnosis. Additional treatments may help control the disease if a relapse occurs.

Treatments for CNS lymphoma have gotten better in recent years. Many people do well with treatment, and survival rates have improved as new treatments are developed.

What affects prognosis

A cancer prognosis helps predict how the cancer may respond to treatment and what to expect. Many factors affect the outlook for CNS lymphoma.

Your prognosis may depend on:

• Your age.
• Your overall health.
• Whether the lymphoma is primary or secondary.
• How much of the brain, spinal cord, cerebrospinal fluid or eyes are affected.
• How well the lymphoma responds to treatment.
• Whether the lymphoma comes back after treatment.
• Whether you have HIV or other conditions that affect your immune system.

For some people, CNS lymphoma may go into long-term remission after treatment. For other people, it can come back and may need more treatment.

If you have questions about prognosis or survival rates, talk with your healthcare team. Your care team can help you understand what these numbers may mean for you.