What is splenic marginal zone lymphoma (SMZL)?

SMZL is a slow-growing type of non-Hodgkin lymphoma (NHL). It develops when B-cells (also called B-lymphocytes) become abnormal. B-cells are white blood cells that fight infection.

The abnormal B-cells (lymphoma cells) build up in the spleen, bone marrow and blood.

The spleen is an organ in the upper part of the abdomen, on the left-hand side. It is normally about the size of a clenched fist. It helps us to fight infection and removes old and damaged blood cells from the bloodstream.

The bone marrow is in the middle of bones. It is where blood cells are made.

A diagram showing the network of lymph nodes throughout the body:

The lymphatic system

Symptoms of splenic marginal zone lymphoma (SMZL)

Many people will have no symptoms when SMZL is first diagnosed. It is sometimes discovered during an examination of your tummy (abdomen) or when blood tests are done for some other reason.

The spleen may become bigger (called splenomegaly) if lymphoma cells build up there. This can cause discomfort or pain in the upper part of the abdomen.

Some people with SMZL have low numbers of blood cells in their blood. The main cause is usually an enlarged spleen removing too many blood cells. It can also happen if lymphoma cells build up in the bone marrow. These cells take up space, which makes it difficult for the bone marrow to make enough blood cells.

If you have too few blood cells, you may:

  • feel tired
  • become breathless when moving around
  • bruise or bleed easily.

Sometimes the lymphoma cells make an abnormal protein called a ‘globulin’ or a ‘paraprotein’. This is found in the bloodstream. This protein can make the blood thicker and more slow-moving than normal. This can cause headaches, confusion, nosebleeds and blurred vision.

B symptoms

Some people also have:

  • drenching night sweats
  • high temperatures (fevers) with no obvious cause
  • unexplained weight loss

Doctors call this group of symptoms B symptoms.

Causes and risk factors of splenic marginal zone lymphoma (SMZL)

SMZL is rare. It is not usually clear why SMZL develops in most people. But some cases may be linked to long-term infection with the hepatitis C virus (HCV). SMZL lymphoma is not infectious and cannot be passed on to other people. It is most common in people over the age of 65.

We have more information about causes and risk factors of lymphoma.

Diagnosis of splenic marginal zone lymphoma (SMZL)

If you have an operation to remove the spleen, it will be sent to a laboratory and tested for SMZL. For people who do not have this operation, SMZL is diagnosed through a combination of:

Other tests may include:

  • Blood tests

    There are many different types of blood test. Your doctor will decide which tests you need.

  • Scans

    There are different types of scans used to help diagnose lymphoma. Scans take pictures of the inside of your body.

  • Bone marrow samples

    A doctor or nurse takes a small sample of bone marrow from the back of the hip bone (pelvis). The sample is sent to a laboratory to be checked for abnormal cells.

Other tests may be done to check for signs of infection with hepatitis C virus.

Doctors use these tests to find out more about the lymphoma.

Waiting for test results can be a difficult time. It may help to talk to your family, friends or specialist nurse.

Staging and grading of splenic marginal zone lymphoma (SMZL)

The results of your tests help your doctors find out how many areas of the body are affected by lymphoma and where these areas are. This is called staging.

Lymphomas are also grouped as either low-grade or high-grade. Low-grade lymphomas are usually slow growing and high-grade lymphomas grow more quickly.

SMZL is a low-grade lymphoma and usually develops slowly. Sometimes it can change (transform) to become a high-grade lymphoma.

We have more information about staging and grading of non-Hodgkin lymphoma.

Treatment for splenic marginal zone lymphoma (SMZL)

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor or cancer specialist or nurse will explain the different treatments and their side effects. They will also talk to you about things to consider when making treatment decisions.

SMZL usually develops slowly. Some people may not need treatment for months or years. During this time they will have regular check-ups to monitor the lymphoma. This is called watch and wait.

Treatment depends on the stage of the lymphoma and whether you have symptoms that are causing problems. The most common treatments are:

  • Targeted therapy

    The targeted therapy drug rituximab is often used on its own or with chemotherapy to treat SMZL.

  • Chemotherapy

    Chemotherapy is an important treatment for SMZL and can often get the lymphoma into remission. It is usually given in combination with rituximab.

    The following drugs may be used to treat SMZL:

    • R-CVP
    • R-CHOP
    • R-chlorambucil – which includes rituximab and the chemotherapy drug chlorambucil.
    • R-bendamustine – which includes rituximab and the chemotherapy drug bendamustine.
  • Steroids

    Steroids are drugs that are often given with chemotherapy to treat lymphomas. They help make chemotherapy more effective.

  • Surgery to remove the spleen (splenectomy)

    An operation to remove the spleen may sometimes be useful in this type of lymphoma. If the spleen is not too large, this operation can be done using laparoscopic surgery (sometimes called keyhole surgery).

  • Radiotherapy

    Radiotherapy uses high-energy rays to destroy cancer cells, while doing as little harm as possible to normal cells. You may have low doses of radiotherapy to the spleen. This treatment may be used if the enlarged spleen is causing symptoms, but you are not well enough to have surgery or chemotherapy.

You may have some treatments as part of a clinical trial.

Unfortunately, SMZL usually cannot be cured. For most people, the aim of treatment is to get rid of as much of the lymphoma as possible. If there are no signs of SMZL after treatment, this is called a complete remission. If SMZL comes back after treatment, further treatment can often successfully get the lymphoma back into remission again.

After splenic marginal zone lymphoma (SMZL) treatment

You have regular follow-up appointments after treatment. These appointments are a good opportunity for you to talk to your doctor or nurse about any concerns you have. Your doctor will want to know how you are feeling generally, and to check you are recovering from any side effects of treatment.

Late effects

Sometimes a side effect may continue or develop months or years after treatment. This is called a late effect.

We have more information about long-term and late effects of treatment for lymphoma.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment.

Making small changes such as eating well and keeping active can improve your health and wellbeing and help your body recover.

Getting support

Everyone has their own way of dealing with illness and the different emotions they experience. You may find it helpful to talk things over with family and friends or your doctor or nurse.

Macmillan is also here to support you. If you would like to talk, you can:

The organisations below also offer information and support:

  • Blood Cancer UK

    Blood Cancer UK is a blood cancer research charity that provides information and support on any type of blood cancer.

  • Lymphoma Action

    Lymphoma Action gives emotional support, advice and information on all aspects of Hodgkin lymphoma and non-Hodgkin lymphoma. It has a national network of people with lymphoma, and local groups.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Professor Rajnish Gupta, Macmillan Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Reviewed: 31 January 2018
Reviewed: 31/01/2018
Next review: 31 July 2020
Next review: 31/07/2020