This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was reviewed on May 31, 2022.
Marginal zone lymphoma (MZL) is a cancer of the lymphatic system—a widespread network of lymph nodes, organs and other structures that make up part of your immune system. Just as blood vessels transport blood, the lymphatic system’s job is to transport lymph, a fluid that contains disease-fighting cells.
Lymphomas are often classified based on how quickly they spread, and marginal zone lymphoma is usually a slow-growing (or indolent) cancer. It is a type of non-Hodgkin B-cell lymphoma. MZL patients make up about 8 percent of non-Hodgkin lymphoma (NHL) cases, according to the Lymphoma Research Foundation.
The National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program estimates that about 81,560 NHL cases were diagnosed in the United States in 2021, which means about 6,500 people diagnosed with MZL.
Marginal zone lymphoma begins in B-cells, a specific type of immune system cell carried within lymph. B-cells help protect against germs by identifying potentially dangerous invaders and signaling other immune system cells to attack them.
B-cells are present throughout your lymphatic system, but MZL can form in three areas:
The three subtypes of MZL, based on where the cancer originated, are as follows:
Extranodal marginal zone B-cell lymphoma, or mucosa-associated lymphoid tissue (MALT) lymphoma, is the most common type. It is called “extranodal” because it doesn’t start in lymph nodes. Instead, it forms in other lymphatic tissue found throughout the body. MALT lymphoma that begins in the stomach is known as gastric MALT lymphoma, and has been linked to an overgrowth of Helicobacter pylori (H. pylori) bacteria. This is often first treated with antibiotics to target the bacteria. In other cases, MALT lymphomas can form in other areas, including the skin, thyroid, lungs, bowels, salivary glands or around the eye. MALT lymphoma is usually slow-growing and responds well to treatment.
Splenic marginal zone B-cell lymphoma is a more rare lymphoma found in blood, bone marrow and the spleen. As with other types of MZL, it tends to grow and spread slowly, and treatment may be safely delayed unless symptoms or other problems arise.
Nodal marginal zone lymphoma is much more rare. It starts within lymph nodes and doesn’t often spread beyond them, and it’s usually slow-growing.
Lymphoma is caused by changes (mutations) within genes. Lymphoma-causing mutations are usually acquired, meaning that they arise during one’s lifetime instead of as inherited mutations that are passed from parent to child. Countless factors can damage your DNA (genetic material) and trigger a mutation. Smoking cigarettes is a common example of a behavior that can harm DNA and increase the risk of certain cancers.
Mutations linked to lymphoma are sometimes spurred by certain chronic infections, autoimmune diseases or other immune system problems. However, mutations can also arise randomly when one of the trillions of cells in your body copies its DNA to form new cells. Scientists haven’t yet identified the specific mutations linked to MZL, but they do know of some factors that can increase the risk of developing MZL, including:
Certain bacterial infections, such as those caused by H. pylori. An overgrowth of this bacteria has been linked to cases of MALT lymphoma in the stomach. Other bacteria, including Chlamydophila psittaci and Campylobacter jejuni, are also associated with an increased risk of MALT lymphoma.
Chronic hepatitis C infection. Having a long-term infection with the hepatitis C virus may increase your risk of developing splenic marginal zone lymphoma and nodal marginal zone lymphoma.
Some autoimmune diseases, including lupus and rheumatoid arthritis. These and other autoimmune conditions are sometimes linked to MALT lymphomas that occur outside of the stomach.
MZL most often affects adults older than 60. Being male is also considered a risk factor for non-Hodgkin lymphoma. However, nodal marginal zone lymphomas are more likely to affect women.
The potential symptoms of MZL may differ depending on the type and location of the cancer. Many of these cancers don’t cause symptoms.
In general, lymphomas that affect B-cells may sometimes cause what are called “B symptoms,” such as:
Below are symptoms associated with each type of MZL.
The process of diagnosing marginal zone lymphoma will likely start with a physical examination, during which your doctor will touch lymph nodes and other areas to check for swelling. The doctor will also ask about your medical history to better understand your health and any potential risk factors.
If a lymphoma is suspected, your doctor may recommend a series of tests, including:
A biopsy is usually needed to make a definitive diagnosis. It helps determine the exact subtype of the cancer, which is crucial to your treatment. A surgical biopsy may be required to remove the spleen or an enlarged lymph node (or a portion of the lymph node) that is suspected of being cancerous.
After the biopsy procedure, the tissue sample is sent to a laboratory, where an expert in cell analysis, called a pathologist, will examine it. If the specimen contains cancerous cells, the pathologist performs tests to identify what types of cancer cells are present.
Marginal zone lymphoma may not always need treatment right away. This treatment approach, called watchful waiting, involves regular checkups to monitor for symptoms and signs that the cancer is growing. This method is most often used for splenic marginal zone or nodal marginal zone lymphomas.
Treatments for MZL depend on the type. Below are some of the most common approaches for each type.
Your care team will help you through all the stages of diagnosis and treatment and provide recommendations based on your test results. Learning as much information as you can will help you make important treatment decisions along the way.