What is MALT lymphoma (extranodal marginal zone lymphoma)?

MALT lymphoma is a slow-growing type of non-Hodgkin lymphoma. Like all lymphomas, it is a cancer of the lymphatic system, which is part of the body’s immune system. It develops when white blood cells called B-lymphocytes become abnormal and begin to grow in an uncontrolled way.

MALT lymphoma affects lymphatic tissue called mucosa-associated lymphoid tissue (MALT). Mucosa is the name for the tissue that lines some organs in the body.

The most common area for MALT lymphoma to develop is the stomach. But it may start in other parts of the body, including the:

  • lung
  • skin
  • thyroid gland
  • salivary gland
  • bowel
  • eye.

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Symptoms of MALT lymphoma

The symptoms depend on where in the body the lymphoma started.

For example, MALT lymphoma in the stomach may cause symptoms such as:

  • indigestion
  • loss of appetite
  • feeling sick (nausea).

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 of MALT lymphoma

MALT lymphomas usually start in areas of the body where there has been long-term inflammation. This may be due to an infection or autoimmune condition in that area. In autoimmune conditions, the body’s immune system attacks body tissue rather than protecting it.

MALT lymphoma is not infectious and cannot be passed on to other people.

  • Infection

    Most MALT lymphomas in the stomach are linked to infection with bacteria called Helicobacter pylori (H. pylori). If H. pylori infection is not treated, it can cause long-term inflammation of the stomach lining. Over time, this may lead to MALT lymphoma developing.

    Other types of bacterial infection have been linked to MALT lymphoma in the skin, eye and bowel.

    Long-term infection with the virus hepatitis C is also a risk factor for MALT lymphoma.

  • Autoimmune conditions

    Autoimmune conditions such as Hashimoto’s thyroiditis and Sjögren’s syndrome have been linked to MALT lymphoma in the thyroid gland, salivary glands and lungs.

    • In Hashimoto’s thyroiditis, the immune system attacks the thyroid gland. This makes it underactive.
    • In Sjögren’s syndrome, the immune system attacks glands that make fluid. This causes dry eyes and a dry mouth.

Diagnosis of MALT lymphoma

MALT lymphoma is diagnosed by doctors taking tissue samples (biopsies) from the affected area. The biopsies are sent to a laboratory for testing and to be examined under a microscope.

If you might have MALT lymphoma in the stomach, your doctor will do an endoscopy. During the endoscopy, they take biopsies from different areas of the stomach.

You can read more about further tests you may have in our information about non-Hodgkin 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 MALT lymphoma

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.

In MALT lymphoma of the stomach, doctors also measure how far the lymphoma has spread from the lining of the stomach into deeper layers of the stomach.

Most MALT lymphomas are diagnosed at an early stage.

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.

MALT lymphoma is a low-grade lymphoma, but rarely it can change (transform) to become a high-grade lymphoma.

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

Treatment for MALT lymphoma

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.

Treatment for MALT lymphoma is usually very successful.

Treatment depends on the type of MALT lymphoma and the stage it is at.

  • Watch and wait

    If the lymphoma is growing very slowly and not causing any problems, you may not need any treatment for some time. Your doctor will monitor you closely so that if the lymphoma does start to grow, they can start your treatment. This is called watch and wait.

  • Antibiotics

    If you have MALT lymphoma in the stomach, you will have tests to check for an infection caused by the bacteria called H. pylori. If you have this, you will have a treatment called triple therapy to get rid of the infection. This involves taking a course of 2 antibiotics and a treatment to reduce the amount of acid made by the stomach.

    Getting rid of H. pylori may clear all signs of the lymphoma (called remission). But this may take several months. After triple therapy, you will have regular endoscopies to check for lymphoma in the stomach. This is to check the lymphoma is shrinking and that you do not need further treatment.

    People who have MALT lymphoma of the eye (orbital MALT) may also be treated with antibiotics. This may make the lymphoma shrink or disappear. It can take several months for this to happen.

  • Radiotherapy

    Radiotherapy may be used to treat localised MALT lymphoma in the stomach that:

    • is not caused by H. pylori
    • has not got better with antibiotic treatment.

    Radiotherapy may also be used to treat localised MALT lymphoma in other parts of the body.

  • Chemotherapy

    Chemotherapy is often given together with a targeted therapy called Rituximab.

    Commonly used chemotherapy treatments include:

    When these treatments are given with rituximab, R is added to the name, for example R-CVP or R-bendamustine.

  • Targeted therapies

    The drug rituximab is often used with chemotherapy to treat this type of lymphoma.

  • Surgery

    Surgery is occasionally used to remove early-stage MALT lymphomas outside of the stomach. This may be done during a test to diagnose the lymphoma or if other treatments are not suitable.

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

After MALT lymphoma 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, Dr Anne Parker, Consultant Haematologist.

    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
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Next review: 31 July 2020
Next review: 31/07/2020