Non-Hodgkin Lymphoma (Adults)

About non-Hodgkin lymphoma

Non-Hodgkin lymphoma starts in white blood cells called lymphocytes.

Lymphocytes make up most of your lymph system, also known as your lymphatic system. Your lymph system is part of your immune system, which helps fight infections and other diseases. Your lymph system also helps control the flow of fluids in your body.

You might also hear non-Hodgkin lymphoma called NHL, or just lymphoma.

Non-Hodgkin lymphoma is actually a group of many different lymphomas that all share some of the same traits. These lymphomas usually start in lymph nodes or other lymph tissue, but they can also start in the skin or any other organ in the body.

See Lymphoma of the Skin to learn more about NHL that affects the skin.

Where in the body does non-Hodgkin lymphoma start?

Lymph tissue is in many parts of your body, so non-Hodgkin lymphoma can start almost anywhere.

• It most often starts in a lymph node. The lymph node can be anywhere in your body.
• It can also start outside the lymph nodes. For example, it can start in your stomach, intestines, skin, or other organs.

The main sites of lymph tissue are your lymph nodes, spleen, bone marrow, thymus, adenoids and tonsils, and digestive tract (stomach, intestines, and other organs).

How is non-Hodgkin lymphoma different from Hodgkin lymphoma?

There are 2 main types of lymphoma:

• Non-Hodgkin lymphoma (NHL)
• Hodgkin lymphoma (HL)

Both start in white blood cells called lymphocytes. Most lymphomas of both types start in a kind of lymphocyte called a B cell. Some non-Hodgkin lymphomas start in other kinds of lymphocytes, called T cells or natural killer (NK) cells.

This information is about non-Hodgkin lymphoma. To learn about HL, see Hodgkin Lymphoma.

Types of non-Hodgkin lymphoma

There are many types of NHL. Classifying them can be complex. But it’s important for your cancer care team to figure out exactly which one you have. This will help them identify your treatment options.  

A lymphoma’s type is determined by many factors.

The most widely used system today is the World Health Organization (WHO) classification. This system groups lymphomas based on:

• The type of lymphocyte the cancer starts in. This could be B cells, T cells, or another type.
• How it looks under a microscope.
• The genetic features of the lymphoma cells.
• The presence of certain proteins on the surface of the cells.
• How fast the lymphoma grows and spreads.
• How serious of a threat it is to your health.

B-cell vs. T-cell lymphomas

There are 2 main types of lymphocytes:

• B lymphocytes (B cells) make proteins called antibodies that help protect your body against germs (bacteria or viruses). Antibodies attach to the germs, marking them for destruction by other parts of the immune system.  Some B cells also "remember" germs your body has fought before. This helps your immune system respond faster if you're exposed again.
• T lymphocytes (T cells) have several roles. Some T cells destroy germs or abnormal cells in the body. Other T cells help boost or slow the activity of other immune system cells.

Lymphoma can start in either type of lymphocyte, but B-cell lymphomas are more common.

Indolent vs. aggressive lymphomas

Non-Hodgkin lymphomas can also be grouped based on how fast they grow and spread.

• Indolent lymphomas grow and spread slowly. Some indolent lymphomas might not need to be treated right away but can be watched closely instead. The most common type of indolent lymphoma in the United States is follicular lymphoma.
• Aggressive lymphomas grow and spread quickly. They usually need to be treated right away. The most common type of aggressive lymphoma in the United States is diffuse large B-cell lymphoma (DLBCL).

Some types of lymphoma, like mantle cell lymphoma, don’t fit neatly into either of these groups.

All non-Hodgkin lymphomas tend to spread to other parts of the lymph system if the cancer is not treated. This is true both for slow-growing and aggressive lymphomas. Eventually, the lymphoma can also spread to other parts of the body, such as the liver, brain, or bone marrow.

Most lymphomas are presumed to have spread by the time they are discovered. Because of this, the stage of a lymphoma is often less important than it is for other types of cancer.