Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT)

Learn about this type of non-Hodgkin lymphoma that can attack many organs including the stomach, small intestine and the eyes. Find out about symptoms, diagnosis and treatments.

Update Date: 08.05.2026

Overview
Symptoms
Causes
Risk factors
Complications
Diagnosis
Treatment
Coping and support
Preparing for an appointment
Stages

Overview

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a type of slow-growing lymphoma. The name often is shortened to MALT lymphoma. Lymphoma is cancer that affects the lymphatic system, which is part of the body's immune system.

In MALT lymphoma, the cancer starts in infection-fighting white blood cells in the moist tissue that lines the inside of the nose, mouth, lungs and digestive system. This tissue is called the mucosa. MALT starts in a type of white blood cell called B cells, also called B lymphocytes.

MALT lymphoma happens when the B lymphocytes grow out of control and form a growth of cancer cells in the mucosa. It can happen after long-term infection or irritation in the tissue. For example, an infection with Helicobacter pylori is linked to MALT lymphoma in the stomach. The body sends white blood cells to fight the infection. Over time, this ongoing immune system response can cause changes in some B cells and lead them to grow out of control.

MALT lymphoma can develop in many parts of the body. It happens most often in the stomach. It also can happen in the lungs, thyroid, salivary glands and eyes.

Not all people with MALT lymphoma need treatment at first. If there are no symptoms, healthcare professionals will typically monitor them. Treatment may depend on where the cancer is located. Options may include chemotherapy, immunotherapy, radiation therapy, targeted therapy and bone marrow transplant, also called bone marrow stem cell transplant.

Lymphomas are often grouped into two main types: Hodgkin lymphoma and non-Hodgkin lymphoma. MALT lymphoma is a type of non-Hodgkin lymphoma. More specifically, it is a type of marginal zone lymphoma. MALT lymphoma also is called extranodal marginal zone lymphoma.

Healthcare professionals typically place MALT lymphoma into two categories: stomach-related and not stomach-related. The types of MALT lymphoma include:

Stomach-related MALT lymphoma. This cancer also is called gastric MALT lymphoma. It's the most common type. It starts in the stomach lining. It is typically linked to an H. pylori infection. H. pylori is a type of bacteria that causes irritation and ulcers in the stomach.

Nonstomach-related MALT lymphoma happens in other parts of the body. It can include:

  • Immunoproliferative small intestinal disease. This type appears in the small intestine and may begin in the duodenum, which is the first short section of the small intestine, just past the stomach.
  • Ocular adnexal MALT lymphoma. This type affects the tissues around the eye, including the tear gland. It may be linked to Chlamydia psittaci infection.
  • Salivary gland MALT lymphoma. This type starts in the salivary glands, which is the place where saliva or spit forms. It is usually linked to Sjogren syndrome.
  • Pulmonary MALT lymphoma. This type starts in the lung. It is also called bronchial-associated lymphoid tissue (BALT) lymphoma.
  • Thyroid MALT lymphoma. This type starts in the thyroid gland. It is typically linked to Hashimoto's disease.

Other, more rare types of MALT lymphoma may affect the breasts, liver and genitourinary (GU) tract. The GU tract involves the urinary system and nearby reproductive organs and includes the bladder, prostate, kidney and uterus.

Symptoms

Signs and symptoms of MALT lymphoma usually depend on what part of the body is involved. In some MALT lymphoma types, there are no noticeable symptoms early on.

MALT lymphoma in the stomach may cause weight loss and general stomach symptoms including:

  • A feeling of sour liquid traveling upward in the throat, called reflux.
  • Discomfort or pain in the stomach.
  • Nausea.

MALT lymphoma can affect other parts of the body:

  • In the salivary glands, it may cause swelling in the face and a tumor in the gland.
  • In the structures surrounding the eye, called the ocular adnexa, it may cause a tumor, eye redness, constant eye watering, swelling around the eye.
  • In the lungs, there may be no symptoms at first. A cough or a shortness of breath may develop. A small nodule or lump may appear on pictures taken of the lungs. Often it is found on a chest X-ray or other imaging test before it causes symptoms.
  • In the thyroid, it may cause a growing tumor in the neck that may be painless. The tumor may lead to trouble swallowing, eating or drinking, and hoarseness.

When to see a doctor

Make an appointment with a healthcare professional if you have symptoms that worry you or are not going away.

Causes

It's not always clear what causes MALT lymphoma. This cancer usually does not come from one cause. It is typically linked to ongoing irritation or inflammation caused by infections. Over time, this inflammation can make certain B cells, which are a type of white blood cell, grow in an irregular way and turn into cancer cells.

Risk factors

The factors that increase the risk of MALT lymphoma may include:

  • Ongoing infections. Ongoing infections can increase the risk of developing MALT lymphoma. These may include H. pylori, Chlamydia psittaci, Borrelia burgdorferi, Campylobacter jejuni and hepatitis C.
  • Autoimmune conditions. Having an autoimmune condition in which the immune system attacks the body by mistake can increase your risk of MALT lymphoma. Such conditions include Hashimoto disease, Sjogren syndrome and others.
  • Older age. MALT lymphoma can happen at any age. It is most common in people age 60 and older.

There is no known way to prevent MALT lymphoma.

Complications

MALT lymphoma complications usually depend on the type. Internal bleeding and organ damage may be complications of gastric MALT lymphoma. In rare situations, a slow-growing MALT lymphoma may turn into a more fast-growing type, such as diffuse large B-cell lymphoma. MALT lymphoma also might come back after treatment. This is known as a relapse. Repeated relapses can be common, depending on where the lymphoma started and how advanced it is.

Diagnosis

An extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) diagnosis begins with a physical exam. A healthcare professional will ask you about your symptoms and discuss your medical history with you. A physical exam will usually check for swollen lymph nodes. Other tests and procedures may include blood tests, tests for certain infections, imaging tests, lymph node biopsy and bone marrow biopsy.

If MALT lymphoma is suspected in your stomach, a healthcare professional may order a procedure called an upper endoscopy.

The healthcare team uses the results to find more information about the type of MALT lymphoma that you have.

Blood tests

Blood tests can sometimes show whether lymphoma cells are present. Blood tests also can check for infections that may increase the risk of MALT lymphoma, such as hepatitis C.

Imaging tests

An imaging test takes pictures inside the body. It can show the location and extent of the MALT lymphoma. If there is concern that the cancer cells have spread to other parts of the body, your healthcare professional might suggest imaging tests. These might include a computerized tomography scan, also called a CT scan, or a positron emission tomography (PET) scan.

Biopsy

Your healthcare professional may suggest a biopsy of the affected organ to look for cancer cells. A biopsy is a procedure to remove a sample of tissue for testing in a lab. In the lab, tests may show whether you have MALT lymphoma.

Bone marrow aspiration and biopsy

Bone marrow aspiration and biopsy are procedures that involve collecting cells from the bone marrow. The cells are sent for testing.

In a bone marrow aspiration, a needle is used to draw a sample of the fluid. In a bone marrow biopsy, a needle is used to collect a small amount of solid tissue. The samples are typically taken from the hip bone and sent to a lab. In MALT lymphoma, this procedure is done to help determine the cancer's extent.

Endoscopy

An upper endoscopy uses a tiny camera on the end of a flexible tube to visually examine the upper digestive system. A healthcare professional passes the tube down your throat and into your stomach to look for signs of cancer.

Testing lymphoma cells in the lab

Lymphoma cells collected from an endoscopy, lymph node biopsy, or bone marrow aspiration and biopsy go to a lab for testing. In the lab, specialized tests look for specific things about the cells. The healthcare team uses the results to find out the type of lymphoma that you have.

To decide whether the cells are MALT lymphoma cells, the healthcare professionals in the lab look for:

  • Proteins on the surfaces of the cancer cells. The cells can be identified by the presence of certain proteins on their surfaces. These proteins are known as markers.
  • Changes in the cancer cells' DNA. Cancer happens when cells get changes in their DNA. A cell's DNA holds the instructions that tell a cell what to do. These changes can cause the cancer cells to multiply rapidly.

Endoscopy

An endoscopy procedure involves inserting a long, flexible tube called an endoscope down your throat and into your esophagus. A tiny camera on the end of the endoscope allows views of your esophagus, stomach and the beginning of your small intestine, called the duodenum.

Treatment

Not all people with MALT lymphoma need treatment at first. If there are no symptoms, healthcare professionals will typically monitor their patients. MALT lymphoma is often treatable, but it is not always curable. Treating MALT lymphoma depends on its stage, the type and the part of the body where it is located.

In certain MALT lymphoma types, medicine is given to treat the underlying infection. In gastric MALT lymphoma, antibiotic medicine is given to treat the H. pylori infection.

Treatments typically include chemotherapy, immunotherapy, radiation therapy, targeted therapy and bone marrow transplant, also called bone marrow stem cell transplant.

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. For MALT lymphoma, the energy beams are most often X-rays or electrons.

Medicines

Medicines to treat MALT lymphoma include:

  • Chemotherapy. Chemotherapy treats cancer with strong medicines. The medicines kill the cancer cells.
  • Targeted therapy. Targeted therapy for cancer is a treatment that uses medicines that attack specific chemicals in the cancer cells. By blocking these chemicals, targeted treatments can cause cancer cells to die.
  • Immunotherapy. Immunotherapy for cancer is a treatment with medicine that helps the body's immune system kill cancer cells. The immune system fights off diseases by attacking germs and other cells that shouldn't be in the body. Cancer cells survive by hiding from the immune system. Immunotherapy helps the immune system cells find and kill the cancer cells.

Bone marrow transplant

A bone marrow transplant, also called a bone marrow stem cell transplant, involves putting healthy bone marrow stem cells into the body. These cells replace cells hurt by chemotherapy and other treatments. Though not used often, a bone marrow transplant might be used when MALT lymphoma is far along or comes back after other treatments.

The cancer prognosis tells you how likely it is that the cancer can be treated successfully. Your healthcare team can get a general sense of your outlook based on the stage of the cancer when you were first diagnosed and other factors such as your overall health and the type of treatment you received.

MALT lymphoma usually is a slow-growing lymphoma. It has a better outcome when it is found early.

The five-year survival rate for gastric MALT lymphoma is 93%. The five-year survival rate for nongastric MALT lymphoma is 88%.

The cancer typically gets harder to treat as the stage advances. MALT lymphoma also can be harder to treat if it turns into a more fast-growing type of cancer, such as diffuse large B-cell lymphoma.

Your healthcare team will speak with you about treatment options that will give you the opportunity for a desirable outcome.

Coping and support

Learning that you have MALT lymphoma can be hard. With time, you’ll find ways to cope that work for you.

Learn about MALT lymphoma

Learn enough about your cancer to feel OK making decisions about your treatment and care. Talk with your healthcare team. Ask your care team to recommend good sources to use for more information.

  • Find a good listener. Finding someone who is willing to listen to you talk about your hopes and fears can be helpful as you manage a cancer diagnosis. This might be a friend or family member. A counselor, medical social worker or clergy member also may offer helpful guidance and care.
  • Join a support group. Ask your healthcare team about local or online groups. Find support online through Mayo Clinic Connect, a community where you can connect with others for support, practical information and answers to everyday questions.

Preparing for an appointment

Start by making an appointment with a doctor or other healthcare professional if you have symptoms that worry you or are not going away.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do before you go. For example, you may be told not to eat before you have a certain test. Make a list of:

  • Your symptoms, including any that don't seem related to the reason for your appointment, and when they began.
  • Key personal information, including major stresses, recent life changes and family medical history.
  • All medicines, vitamins and other supplements you take, including doses.
  • Questions to ask your healthcare professional.

Bring a family member or friend with you, if possible, to help you remember the information you're given in case you feel overwhelmed at the appointment.

For MALT lymphoma, some basic questions to ask include:

  • What's likely causing my symptoms?
  • Other than the most likely cause, what are other possible causes for my symptoms?
  • What tests do I need?
  • What's the best course of action?
  • I have other health conditions. How can I best manage them together?
  • Are there restrictions I need to follow?
  • Should I see a specialist?
  • Are there brochures or other printed material I can have? What websites do you suggest?

Be sure to ask any other questions you may have to understand what is ahead.

What to expect from your doctor

Your healthcare professional may ask you questions, such as:

  • When did your symptoms first begin?
  • Do you have symptoms all the time? Or do they come and go?
  • How bad are your symptoms?
  • What, if anything, seems to make your symptoms better?
  • What, if anything, seems to make your symptoms worse?

Stages

If you're diagnosed with MALT lymphoma, the next step is to find out how much and where the cancer has spread. This is called the stage. Healthcare professionals may use imaging and biopsies to determine the stage by looking at how big the cancer is and its location. Your healthcare team creates your treatment plan based on your stage.

The stages of MALT lymphoma range from 1 to 4. A higher stage number means the cancer is more advanced.

For gastric MALT lymphoma, the stages include 1, 2 and 4. There is no stage 3.

  • Stage 1. At this stage, the cancer is confined to the gastrointestinal tract.
  • Stage 2. At stage 2, the cancer has spread into the abdomen and nearby lymph nodes.
  • Stage 4. At stage 4, the cancer is found in multiple sites outside of the lymph nodes or has spread to other organs.

For nongastric MALT lymphoma, the stages include 1, 2, 3 and 4.

  • Stage 1. Typically, one lymph node or one group of lymph nodes is affected. Or a single area outside the lymph node is affected.
  • Stage 2. Two or more lymph node regions on the same side of the diaphragm are involved, with or without a small amount of spread to outside the lymph nodes.
  • Stage 3. Lymph node regions on both sides of the diaphragm are affected. Or lymph nodes above the diaphragm and the spleen are affected.
  • Stage 4. The MALT lymphoma has spread outside of the lymph nodes. The spread is usually to organs, including the bone marrow, liver and lungs.

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