Doctors put NHL into 2 groups, depending on how quickly they are likely to grow and spread.
The 2 groups are low grade and high grade. The different grades of NHL are treated in slightly different ways.
Low grade NHL tends to grow very slowly. Doctors call them indolent lymphomas.
Types of low grade NHL
Follicular lymphoma is the most common type of low grade NHL. Other types include:
- mantle cell lymphoma
- marginal zone lymphoma
- small lymphocytic lymphoma
- lymphoplasmacytic lymphoma
- skin lymphoma
Over time, low grade lymphomas may change into a high grade type lymphoma.
Follicular lymphoma is the most common type of low grade lymphoma. Each year around 2,500 people are diagnosed with follicular lymphoma in the UK.
Out of all people with NHL in the UK, just under a fifth (18%) have the follicular type. It mainly affects adults over the age of 60.
Doctors might further sub divide follicular lymphoma into 3 separate grades. These are 1, 2 and 3. To get this grade, doctors looks at your lymphoma cells under a microscope. The grade is based on the number of large, follicular lymphoma cells (centroblasts) that they can see. Grade 3B follicular lymphoma is faster growing and is likely to be treated as a high grade lymphoma.
Mantle cell lymphoma
Mantle cell lymphoma is a rare type of B cell lymphoma.
Each year around 75 people are diagnosed with mantle cell lymphoma in the UK. Out of all people with NHL in the UK, less than 1 in every 100 people (1%) have mantle cell lymphoma.
Even though mantle cell lymphomas are classed as low grade, they might grow quickly. So they might be treated more like high grade lymphomas.
Marginal zone lymphoma
This is a group of slow growing B cell lymphomas.
There are 3 types of marginal zone lymphoma. It is called marginal zone lymphoma because it starts in an area of lymphoid tissue called the marginal zone.
Mucosa associated lymphoid tissue (MALT) lymphoma
This is the most common type of marginal zone lymphoma. You might hear it called extranodal marginal zone lymphoma.
MALT lymphoma does not start in the lymph nodes. It starts in the mucosa, which is a soft, moist tissue layer that protects and covers organs in different parts of your body.
The most common place for it to develop is the stomach. This is called gastric MALT lymphoma.
Less commonly, it can develop in the small bowel, salivary gland, thyroid gland, tear glands or lungs. These lymphomas tend not to spread beyond the place where they started.
Nodal marginal zone lymphoma
This type of marginal zone lymphoma starts within the lymph nodes. It is sometimes called monocytoid B cell lymphoma.
Splenic marginal zone lymphoma
This type of marginal zone lymphoma starts in the spleen but can also be found in the bloodstream.
Small lymphocytic lymphoma
Small lymphocytic lymphoma is also called chronic lymphocytic leukaemia (CLL).
In theory, lymphoma is an illness that starts in the lymph nodes whereas leukaemia is an illness of the blood. But leukaemia and lymphoma have many similarities and often affect the body in similar ways.
Chronic lymphocytic leukaemia is the term used for this condition if many of the abnormal cells are in the blood. Doctors call it small lymphocytic lymphoma when the disease involves the lymph nodes in particular.
Lymphoplasmacytic lymphoma (including Waldenstrom's macroglobulinaemia)
In these low grade lymphomas, abnormal B cells fill up the bone marrow or enlarge the lymph nodes or spleen.
Most of these lymphomas are a type called Waldenstrom's macroglobulinaemia (or immunocytoma). People with Waldenstrom's macroglobulinaemia have a high level of a protein called immunoglobulin M (IgM) in their blood. The protein makes the blood thicker.
Skin (cutaneous) lymphoma is a rare type of NHL.
There are 2 types of lymphocytes or white blood cells. These are T cell or B cells. In cutaneous lymphoma, the T cells or B cells grow out of control within the skin. There are 2 main types of skin lymphoma:
- cutaneous T cell lymphoma (CTCL) starts in the T cells of the skin
- cutaneous B cell lymphoma (CBCL) starts in the B cells of the skin
CTCL is the most common type of skin lymphoma. It causes flat red patches on the skin that look like eczema and can be itchy. Several parts of the body can be affected.
CBCL is a more unusual type. People tend to have lumps on their skin in 1 or 2 areas, rather than affecting all of the body.
Transforming from low grade to high grade
Over time, low grade lymphomas can sometimes change into a faster growing (high grade) lymphoma.
This change is more common in some types of NHL than others. So it does not always happen. If it does, it can happen some years after you are first diagnosed with low grade NHL.
Sometimes, you can have a low grade and higher grade lymphoma at the same time. This can even happen in the same lymph node. Your doctor might assume that your low grade lymphoma is in the process of transforming to the higher grade type if this happens.
After a low grade NHL has transformed, it has to be treated as high grade. Unfortunately, a transformed NHL is generally harder to control than when it was low grade. And the treatment is more intense.
Treatment for low grade lymphomas
The type of treatment most suitable for you depends on your:
- type of lymphoma
- general health