About MALT lymphoma

Lymphoma is a type of blood cancer. Blood cancer happens when some of your blood cells stop working properly.

There are different types of blood cell in the body – red blood cells, white blood cells and platelets. Lymphoma affects white blood cells called lymphocytes. The main job of lymphocytes is to help you fight off infections.

Abnormal lymphocytes cluster together and cause swellings – often these are in the lymph nodes (glands) but they can be in other places.

There are two main types of lymphoma – Hodgkin lymphoma and non-Hodgkin lymphoma. MALT lymphoma is a type of non-Hodgkin lymphoma.

MALT stands for mucosa-associated lymphoid tissue. MALT lymphoma is a type of blood cancer – a slow growing type that can be controlled with treatment.

Mucosa (also known as mucous membrane) lines organs and passages inside your body such as the mouth, throat, stomach, gut and lungs. It contains lymphoid tissue which is full of lymphocytes. This helps protect the body against germs like viruses and bacteria.

In MALT lymphoma, abnormal lymphocytes collect in the lymphoid tissue of the mucosa, causing swellings or lumps.

This usually happens in the stomach (gastric MALT lymphoma). Swellings can also develop in other places such as the lungs, gut, eyes, saliva glands, skin, and thyroid gland (non-gastric MALT lymphoma).

MALT lymphoma is sometimes called “extranodal marginal zone lymphoma”. This is because it develops outside of the lymph nodes (extranodal) in an area at the edge of the lymphoid tissue (the marginal zone).

MALT lymphoma is rare. About 7 percent of people (7 out of every 100) who are diagnosed with blood cancer have MALT lymphoma. It’s more common in people who are older. The average age at diagnosis is around 70 years old.

Researchers think that there is a link between MALT lymphoma and diseases that cause long-term inflammation. Inflammation is part of the normal process of dealing with infection and causes symptoms like redness, swelling and heat. But it can be harmful if it continues over a long period (chronic inflammation).

Inflammation caused by the following infections has been linked with MALT lymphoma:

• Helicobacter pylori (H. pylori) – around 90 percent of people with MALT lymphoma (9 out of 10) show evidence of H. pylori.
• Campylobacter jejuni (C. jejuni) is linked to MALT lymphoma in the small bowel.
• Achromobacter xylosoxidans (A. xylosaxidans) is linked to MALT lymphoma in the lungs, especially in people with a weakened immune system.
• Chlamydophelia psittaci (C. psittaci) is linked to MALT lymphoma in tissue around the eyes.
• Borrelia burgdorferi (B. burgdorferi) is a bacterium passed on by ticks and is linked to Lyme disease and MALT lymphoma in the skin.
• The hepatitis C virus (HCV) has also been linked to MALT lymphoma.

Most people with these infections will not go on to get lymphoma.

These are where the body’s immune system mistakes healthy cells for foreign cells and begins to attack them. This can also cause long-term inflammation.

The following conditions have been linked to MALT lymphoma:

• Sjögren’s syndrome: this affects glands that secrete fluids such as tears and spit. It may be linked to MALT lymphoma in the saliva glands.
• Hashimoto's thyroiditis: this causes a drop in levels of thyroid hormones and may be linked to MALT lymphoma in the thyroid gland.

Most people with autoimmune conditions will not go on to get lymphoma.

Researchers collect data on how people with cancer respond to treatment. Doctors use this to work out a general picture of what happens to people who are diagnosed with a particular disease. This is called prognosis.

MALT lymphoma is a very rare disease, so there isn’t a lot of data to look at. However, the research we have suggests that the prognosis for MALT lymphoma is very good.

Prognosis also depends on your individual circumstances, including:

• your general health and fitness
• your age
• how early you were diagnosed
• any other health conditions you may have
• the type of MALT lymphoma you have.

Some people don’t want to know about their individual prognosis and others find it helpful. Your team will be there to give you more information about your own outlook or answer any questions.

We have more information about the general prognosis for blood cancer. This includes how to understand statistics you may find online. Sometimes these can be worrying, but it’s important to remember that everyone is different, and your prognosis is individual to you.