Marginal zone lymphomas are B-cell lymphomas. They are not very common and account for a small percentage of non-Hodgkin lymphomas (NHLs). There are 3 main types of marginal zone lymphomas:
Extranodal marginal zone lymphomas start in tissues or organs outside of the lymph nodes (extranodal). MALT lymphoma develops in mucosa-associated lymphoid tissue, in the mucosa or tissue that lines body organs or body cavities including:
MALT lymphomas are the third most common type of NHL and account for about 8% of all cases of NHL. Most MALT lymphomas occur in people in their 60s.
Many people are diagnosed with localized or early stage disease that has not spread elsewhere in the body. MALT lymphomas are usually slow growing (indolent), but some can be high grade. They often remain in the area in which they started for a long period of time. Rarely, MALT lymphomas can change (transform) into a more aggressive large cell lymphoma.
Many people with MALT lymphoma of the stomach (gastric lymphoma) have a history of a bacterial infection caused by Helicobacter pylori (H. pylori). H. pylori weaken the protective mucous coating of the stomach and can cause inflammation of the stomach (gastritis) and stomach ulcers. Not every one that has an H. pylori infection will develop a MALT lymphoma. About 5–10% of people with gastric MALT lymphoma do not have an H. pylori infection (H. pylori negative).
Other MALT lymphomas have been linked to bacterial or viral infections. People with MALT lymphomas in areas of the body other than the stomach often have a history of autoimmuneautoimmuneA disorder in which the immune system attacks healthy tissues in the body. diseases, such as:
MALT lymphomas are usually slow growing (indolent) and often respond well to treatment. Treatment is tailored to the stage, grade and location of the MALT lymphoma.
Early stage MALT lymphomas that occur in areas other than the stomach may be given local treatments, such as surgery or radiation therapy.
More advanced MALT lymphomas (stage III or IV) are usually treated the same as follicular lymphoma.
Treatment of MALT lymphomas of the stomach are discussed below.
MALT lymphomas of the stomach (gastric MALT lymphomas) are staged and treated differently than MALT lymphomas that occur in other parts of the body. People with gastric lymphomas often have early stage disease when their lymphoma is first diagnosed.
Healthcare professionals disagree about the best way to stage gastric MALT lymphoma. The 2 systems used are the Ann Arbor staging system and the TNM staging system.
The Ann Arbor staging system has been modified for gastric lymphomas.
Tumour is confined to the stomach without spread to the lymph nodes.
Tumour extends into the abdomen and has spread to the lymph nodes.
II1 – Cancer has spread to local lymph nodes (such as paragastric nodes).
II2 – Cancer has spread to distant lymph nodes (such as para-aortic, pelvic or inguinal nodes).
Tumour penetrates the serosa to spread to nearby (adjacent) organs or tissues.
Widespread (disseminated) spread to extranodalextranodalOf or affecting an area or organ outside the lymph nodes. sites or spread to the lymph nodes above the diaphragm (supradiaphragmatic nodal involvement).
The TNM staging system for stomach cancer has also been applied to gastric MALT lymphoma. TNM stands for tumour, nodes, metastasis.
The depth that the primary tumour (T) in gastric MALT lymphoma has gone into the layers of the stomach corresponds to the T stage of stomach cancer.
T1m – Lymphoma confined to the mucosa.
T1sm – Lymphoma confined to the submucosa.
Lymphoma invades the muscularis (muscularis propria).
Lymphoma penetrates the subserosa.
Lymphoma has grown through the serosa or invades organs near the stomach.
N is the number and location of any regional lymph nodes that contain cancer cells.
No cancer in regional lymph nodes.
There is cancer in the regional lymph nodes.
M stands for distant metastasis and shows whether the cancer has spread to a different part of the body.
No distant metastasis.
Note: M is not generally used in staging gastric MALT lymphoma.
Treatment options for gastric MALT lymphoma depend on its stage – whether it is localized or more advanced – and how the person responds to initial therapy.
Treatment options for early stage (localizedlocalizedConfined or restricted to the original (primary) site with no evidence of spread.) gastric MALT lymphoma that is confined to the stomach often include:
More advanced gastric MALT lymphomas are often treated like follicular lymphoma.
For more detailed information on specific drugs, go to sources of drug information.