Non-Hodgkin lymphoma

Non-Hodgkin lymphoma is a term used to describe a large group of cancers that start from lymphocytes, a type of white blood cell found in the immune system. Lymphocytes normally help the body fight infection, but in lymphoma, these cells grow uncontrollably and form tumors in lymph nodes or other parts of the body.

Non-Hodgkin lymphoma can arise from B cells or T cells, the two main types of lymphocytes. It may develop in the lymph nodes, which are small structures found throughout the body, or in other organs such as the spleen, bone marrow, gastrointestinal tract, or skin.

Non-Hodgkin lymphoma is different from Hodgkin lymphoma, which is another type of cancer that also starts in lymphocytes but has distinct features under the microscope and responds differently to treatment. The term “non-Hodgkin” is used to group together all types of lymphoma that are not Hodgkin lymphoma.

What are the most common types of non-Hodgkin lymphoma?

There are many different types of non-Hodgkin lymphoma, and they are usually classified based on the type of lymphocyte involved (B cell or T cell), how the cells look under the microscope, and how quickly the lymphoma is likely to grow. Some types grow slowly and may not require immediate treatment, while others grow quickly and need prompt therapy. Below are brief descriptions of some of the most common types of non-Hodgkin lymphoma.

• Diffuse large B-cell lymphoma (DLBCL): This is the most common type of non-Hodgkin lymphoma. It usually grows quickly and requires prompt treatment. It often causes swollen lymph nodes and may affect other organs.
• Follicular lymphoma: This type usually grows more slowly than DLBCL and often begins in the lymph nodes. Some cases may remain stable for many years, while others may eventually transform into a more aggressive form.
• Mantle cell lymphoma: A less common type that usually grows at a moderate pace. It often involves the lymph nodes, spleen, and bone marrow, and may also affect the gastrointestinal tract.
• Marginal zone lymphoma: This group includes several slow-growing lymphomas that often begin in the stomach, salivary glands, thyroid, or spleen. It includes extranodal marginal zone lymphoma (also called MALT lymphoma), nodal marginal zone lymphoma, and splenic marginal zone lymphoma.
• Burkitt lymphoma: A fast-growing type of lymphoma that often affects children and young adults. It is more common in certain parts of Africa but can occur anywhere in the world.
• Lymphoplasmacytic lymphoma (Waldenström macroglobulinemia): A slow-growing lymphoma that produces abnormal proteins in the blood. It often affects older adults and can cause symptoms such as fatigue, bleeding, or nerve problems.
• Peripheral T-cell lymphomas: A group of non-Hodgkin lymphomas that develop from T cells rather than B cells. These are less common and often more aggressive than B-cell lymphomas.

What causes non-Hodgkin lymphoma?

In most cases, the cause of non-Hodgkin lymphoma is unknown. However, certain factors may increase the risk of developing the disease, including:

• A weakened immune system (such as in people with HIV or after organ transplantation).

• Autoimmune diseases.

• Certain infections (such as Helicobacter pylori, Epstein-Barr virus, or HTLV-1).

• Exposure to some chemicals or radiation.

• A personal or family history of lymphoma.

What symptoms are associated with non-Hodgkin lymphoma?

The symptoms of non-Hodgkin lymphoma depend on where the cancer starts and whether it has spread.

Common symptoms include:

• Swollen lymph nodes (in the neck, armpit, or groin).

• Unexplained weight loss.

• Fever.

• Night sweats.

• Fatigue.

• Abdominal pain or swelling.

• Cough or difficulty breathing (if the chest is involved).

Some people have no symptoms at first and the lymphoma is found during a test for another condition.

How is non-Hodgkin lymphoma diagnosed?

The diagnosis is usually made after a biopsy of an enlarged lymph node or other affected tissue. A pathologist examines the tissue under a microscope and uses immunohistochemistry and sometimes molecular tests to determine the exact type of lymphoma. Additional tests, such as blood tests, bone marrow biopsy, and imaging scans (CT, PET), may be used to determine how far the lymphoma has spread. This process is called staging.

What does non-Hodgkin lymphoma look like under the microscope?

Under the microscope, the appearance of non-Hodgkin lymphoma depends on the specific type. In general, lymphoma tissue shows abnormal lymphocytes that are larger, more numerous, or more irregular than normal. Pathologists also look at how the cells are arranged and whether they are growing quickly. Special stains and genetic tests help confirm the diagnosis and guide treatment.

Questions to ask your doctor

• What type of non-Hodgkin lymphoma do I have?

• Is it fast-growing or slow-growing?

• Has the lymphoma spread, and what stage is it?

• What treatments are recommended for my type of lymphoma?

• Are any additional tests needed before starting treatment?