Primary CNS lymphoma

Primary CNS lymphoma is a rare type of lymphoma. Lymphomas usually start in the lymph nodes. These are part of the lymphatic system, which helps the body fight infection and disease. CNS lymphoma starts in the brain or spinal cord (central nervous system). The symptoms may include:

  • changes in behaviour or personality
  • changes in balance and co-ordination
  • numbness or weakness of one side of the body
  • seizures (fits)
  • problems with your vision.

To make a diagnosis, you have a small operation called a biopsy to remove a small part of the tumour. You will have scans to find out more about the size and position of the lymphoma.

Your specialist doctor is usually a haematologist or oncologist with experience of treating CNS lymphoma. Other members of the team who help plan your treatment may include a specialist brain doctor such as a neurologist. They will look at your general health and individual situation before planning treatment.

The main treatment is chemotherapy, usually given with a targeted therapy drug called rituximab. You may have radiotherapy after chemotherapy.

Primary CNS lymphoma

This information describes primary central nervous system (CNS) lymphoma, the symptoms, tests and possible treatments. It is best to read it along with our general information about non-Hodgkin lymphoma and about brain tumours for more on tests, treatments and side effects. We also have information on spinal cord tumours.

We hope this information answers your questions. If you have any further questions, you can ask your doctor or nurse at the hospital where you are having treatment.

What is primary CNS lymphoma?

A lymphoma is a cancer of the lymphatic system, which is part of the body’s immune system and helps fight infection. A CNS lymphoma starts in the brain, the eye or the spinal cord. It begins in cells called lymphocytes (usually B-cell lymphocytes) that are part of the immune system.

Lymphomas that start in the central nervous system (CNS) are called primary CNS lymphomas or PCNSL for short. They are rare and usually grow quickly. They are most likely to affect older people. Most PCNSL are diffuse large B-cell lymphomas (DLBCL).

The central nervous system (CNS) includes the brain, parts of the eye and the spinal cord. The brain controls different functions such as how we think, feel, learn and move. The spinal cord is made up of nerves running down the middle of the back (spine). These nerves carry messages between the brain and other parts of the body.

The most common places for a primary CNS lymphoma to affect are the cerebrum, cerebellum and brain stem. Often, there’s more than one tumour. Less commonly, they may start in other parts of the CNS, including the lining of the brain (meninges), the eye (primary intraocular lymphoma) or the spinal cord.

A lymphoma that starts in another part of the body but is also in the brain at diagnosis, or spreads there later, is called secondary CNS lymphoma.

This information is about lymphoma that starts in the central nervous system called primary CNS lymphoma.

Brain cross section detail
Brain cross section detail

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Causes of primary CNS lymphoma

The cause in most people is not usually known. People whose immune system is not working well may have more risk of developing CNS lymphoma. This includes people with HIV (human immunodeficiency virus) or people who have had an organ transplant. But most people who develop this type of lymphoma have a normal immune system.


Some possible symptoms are:

Changes in behaviour or personality – these are common symptoms in PCNSL, but they may only be noticeable to close family and friends to begin with.

Numbness or weakness – some people may have numbness or weakness on one side of the body.

Changes in balance or movement – your balance and co-ordination are affected, which makes walking more difficult.

Seizures (fits) – some people may have seizures. Our general information on brain tumours has more information on this.

Problems with vision – if the lymphoma starts in the eye or nearby, you may have changes in vision.

Tingling and weakness in the arms or legs – these may be symptoms of lymphoma in the spinal cord or the brain.

Raised intracranial pressure – occasionally the lymphoma causes an increase in pressure in the brain, causing headache, vomiting and problems with your eyesight. This may happen as a result of swelling around the tumour, or a build-up of the cerebrospinal fluid (CSF) that surrounds and protects the brain and spinal cord.


Your doctors need to find out as much as possible about the lymphoma so they can plan the best treatment for you. You will have a number of different tests, which your doctor or nurse will explain to you.

Your specialist will examine you and do checks on your nervous system. These include checking your reflexes and the power and feeling in your arms and legs. They also shine a light at the back of your eye to check if the optic nerve is swollen, which can be a sign of raised pressure in the brain. Your doctor will ask some questions to check your reasoning and memory.

You will have blood tests taken to check the number of cells in your blood (full blood count) and to see how well your kidneys and liver are working. Your doctor or nurse may talk to you about having a test for HIV and for other infections.

You will have a MRI scan and a CT scan to help diagnose the lymphoma and find its exact position.

MRI (magnetic resonance imaging) scan

This test is similar to a CT scan (see below) but uses magnetism instead of x-rays to build up a detailed picture of areas of your body. Before the scan, you may be asked to complete and sign a checklist. This is to make sure it’s safe for you to have an MRI scan.

Before having the scan, you’ll be asked to remove any metal belongings, including jewellery. Some people are given an injection of dye into a vein in the arm. This is called a contrast medium and can help the images from the scan to show up more clearly. During the test, you will be asked to lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It’s painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It’s also noisy, but you will be given earplugs or headphones.

CT (computerised tomography) scan

A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of the body. You will have a full body scan. The scan is painless and takes 10 to 30 minutes. CT scans use small amounts of radiation, which will be very unlikely to harm you or anyone you come into contact with.

You may be given an injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. If you are allergic to iodine or have asthma you could have a more serious reaction to the injection, so it’s important to let your doctor know beforehand.

PET-CT scan

A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body. It is often used in combination with a CT scan to give more detailed information about the part of the body being scanned. A PET-CT scan is used to make sure there is no lymphoma outside the CNS.

You may have to travel to a specialist centre to have a PET-CT scan. You can't eat for six hours before the scan, although you may be able to drink.

A mildly radioactive substance is injected into a vein, usually in your arm. The radiation dose used is very small. The scan is done after at least an hour’s wait. It usually takes 30 to 90 minutes. You should be able to go home after the scan.

Lumbar puncture

You may have a lumbar puncture to check if there are any cancer cells in the fluid that surrounds the spinal cord (called cerebrospinal fluid). Your doctor uses a local anaesthetic to numb the lower part of your back and passes a needle gently into the spine. They take a small sample of the fluid to check for lymphoma cells. You may feel some pressure but it shouldn’t be painful. Once the lumbar puncture is over, you will need to lie on your back for a couple of hours.

Bone marrow sample

You may have this done to make sure the lymphoma has not started outside the brain. A small sample of bone marrow is taken from the back of the hip bone (pelvis). It’s sent to a laboratory to check for abnormal cells. You’ll be given a local anaesthetic injection to numb the area.

The doctor or nurse passes a needle through the skin into the bone. They then draw a sample of liquid and a small core of bone marrow from inside the bone into a syringe. It can feel uncomfortable for a few seconds when the liquid and marrow are being drawn into the syringe. The test takes about 15 to 20 minutes, but removing the bone marrow sample only takes a few minutes.


This is the most important test to diagnose primary CNS lymphoma. You have a small sample of tissue removed from the tumour (biopsy), usually under a general anaesthetic. A neurosurgeon (brain surgeon) makes a small hole in the skull and passes a fine needle through into the tumour. They remove a small sample of tissue, which is examined to find out the type of cells the tumour is made up of.

Someone having a CT scan

Having a CT scan

A radiographer explains how a CT scan works, and Jyoti talks about her experience.

About our cancer information videos

Having a CT scan

A radiographer explains how a CT scan works, and Jyoti talks about her experience.

About our cancer information videos


The main treatment for primary CNS lymphoma is usually chemotherapy. It is often given along with a targeted therapy drug called rituximab (Mabthera®). Before you start chemotherapy, your doctor will usually give you drugs called steroids.

Some people may have radiotherapy after chemotherapy.

A cancer doctor (haematologist or oncologist) who is experienced in treating CNS lymphoma will plan your treatment. They will meet with a team of specialists, which can include doctors who specialise in conditions of the brain (neurologists, neurosurgeons or neuropsychologists) and a specialist nurse.

They look at your individual situation and your general health to plan the best treatment for you. Your specialist will then explain the aims of your treatment, what it involves, and the benefits and disadvantages.

Deciding on the treatments that are right for you is a decision you make with your doctor. Make sure you have enough information and time to help you make any treatment decisions.

Newer types of treatment are being tested in clinical trials. Your doctor will explain more about this. They may ask you to think about taking part in a trial.


Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. It is usually the first treatment for primary CNS lymphoma and given with the targeted therapy drug rituximab.

A nurse will usually give you the chemotherapy drugs into a vein (intravenously). They usually give it to you through a fine tube under the skin of your chest and into a vein close by (central line). Or it may be given through a fine tube into a vein in your arm that goes up into a vein in your chest (PICC line).

Doctors use chemotherapy drugs that can pass through the blood-brain barrier. The blood-brain barrier is part of the brain’s natural protection that stops certain drugs from getting into the brain and spinal cord.

Doctors often use a chemotherapy drug called methotrexate in high doses to treat primary CNS lymphoma. It can be given along with either cytarabine or thiotepa, or both these drugs. You usually have rituximab as well.

Some people have the chemotherapy drugs temozolomide and procarbazine along with methotrexate and rituximab. You take temozolomide and procarbazine as tablets.

Side effects of chemotherapy

Your doctor or specialist nurse will tell you what to expect. They can prescribe medicines to prevent or reduce side effects and give you advice on managing them.

One of the main side effects is risk of infection. Chemotherapy temporarily reduces the number of white blood cells, which help fight infection. You may be given drugs to reduce your risk of getting an infection. Chemotherapy can also affect red blood cells, which carry oxygen around the body, and platelets which help the blood to clot. Other side effects can include feeling sick, sore mouth and hair loss. There are different ways side effects can be controlled or managed. Always let your doctor or nurse know about any side effects you have. We have more detailed information on side effects of chemotherapy.

High-dose chemotherapy with stem cell support treatment

Some people with primary CNS lymphoma have high-dose chemotherapy and stem cell support (autologous transplant). Stem cells are blood cells at their earliest stage of development. Your stem cells are collected from your blood. They are stored until you have high dose chemotherapy to destroy the lymphoma cells. The chemotherapy drugs most commonly used are thiotepa (Tepadina®) and carmustine (BiCNU®)

 After the high-dose chemotherapy, your stem cells are given back to you by a drip (like a blood transfusion). The stem cells make their way to your bone marrow and start to produce blood cells to help you to recover from the effects of chemotherapy.

This intensive treatment is not suitable for everyone. You need to stay in hospital during treatment and for a few weeks after because you are at more risk of an infection and other complications.

We have more detailed information about high-dose chemotherapy with stem cell support.

Targeted therapy

You usually have a targeted therapy drug called rituximab with your chemotherapy. Rituximab attaches itself to a protein on the surface of lymphoma cells and stimulates the body’s immune system to destroy these cells.


Radiotherapy treatment uses high-energy rays to destroy the cancer cells. It may be given after chemotherapy or on its own if you aren’t well enough to have chemotherapy. For PCNSL, you usually need radiotherapy to the whole brain.

If a CNS lymphoma starts in the eye, it can be treated with radiotherapy given directly to the eye.

But not everyone will need radiotherapy. Doctors may use other treatments instead to avoid the possibility of long-term effects of radiotherapy to the brain.

Side effects of radiotherapy

Your doctor and specialist nurse will talk to you about the side effects and the risk of long-term effects.

You will be very tired after radiotherapy and this can carry on for weeks or longer after it finishes. Try to get plenty of rest but balance this with some activity such as short walks. This helps to give you more energy.

The skin on your scalp may become itchy and red or darker, and you will lose the hair in the area being treated. This usually grows back again after two to three months. You will be given advice on looking after the skin on your scalp and coping with hair loss.

Radiotherapy may cause side effects that develop months or years after treatment. These are called late effects and may include changes to your thinking, planning and memory. Sometimes these changes can have a serious effect on a person’s quality of life. Your doctor or nurse will talk to you about this before you have treatment.


You usually start taking steroids after you have had a biopsy. Steroids reduce the swelling around the lymphoma and may also help to shrink it. Your doctor will prescribe steroids if you have raised pressure in the brain or if a lymphoma in the spine is causing pressure. Steroids reduce the pressure, improve the symptoms and help you to feel better. Your doctor may stop the steroids a few weeks after you start chemotherapy.

You usually take steroids as tablets, but they can also be given into a vein (intravenously). Possible side effects of steroids include indigestion, increased appetite, weight gain, feeling restless or agitated and difficulty getting to sleep. Taking steroids with food can help reduce indigestion. Your doctor may also prescribe medication to protect your stomach.

It is very important to take steroids exactly as they have been prescribed. We have more information about steroids.

HIV treatment

If you have HIV, your specialist doctor will advise you to start taking highly active antiretroviral therapy (HAART). HAART works by reducing the level of HIV in the body and improving your immunity. It improves survival in people with HIV-related lymphomas.


Surgery is rarely used to treat primary CNS lymphoma. This is because there are often several tumours or the tumour is deep in the brain.

Medicines for seizures

If you have seizures (fits), your doctor may ask you to take a drug called an anticonvulsant to help prevent them.

Help with your recovery

It may take some time for treatment to improve your symptoms. Some people may need extra support to help them to recover (rehabilitation). Different health professionals can help you with this. Physiotherapists can help you to improve your balance, walking or strength. Speech therapists can help if you have difficulties with speaking or finding the right words. An occupational therapist can provide equipment and help you be more independent at home.

People who have difficulties in thinking (cognitive problems), planning or concentration because of the lymphoma or treatment can be referred to a neuropsychologist. Although it can take time, most people find that with help and support these problems improve or become easier to manage.

Your feelings

Being diagnosed with a brain tumour can feel frightening at times. You may have many different emotions, including anxiety, anger, fear, or feeling low or depressed. Many people go through these feelings in coping with their illness. It’s important to get the support you need.

You may find it helpful to talk things over with family and close friends and with your doctor or nurse. You can also talk to one of our cancer support specialists. Sometimes people need more help to cope with difficult feelings of anxiety or depression. Your doctor can refer you to a counsellor or psychologist for more support.


You will not be allowed to drive for at least two years after treatment finishes, when you can re-apply. Although this can be upsetting, it’s important to follow the advice you are given. If you live in England, Scotland or Wales, your doctor will ask you to contact the Driver & Vehicle Licensing Agency (DVLA). If you live in Northern Ireland, you will need to contact the Driver and Vehicle Agency (DVA). It is your responsibility to do this. Your doctor or nurse can give you more information.

Useful organisations

Driver and Vehicle Licensing Association (DVLA)

The DVLA advises GPs and other members of the medical profession on the medical standards of fitness to drive. Patients should seek advice from their doctors.

The Driver and Vehicle Agency (DVA)

If you live in Northern Ireland, the government services website has information about driving and medical conditions.

The Lymphoma Association

The Lymphoma Association gives emotional support, advice and information on all aspects of lymphoma. It has a national network of people with lymphoma and local groups.