What is lymphoma?

Lymphoma is a cancer of the lymphatic system, which is part of the body's immune system. It starts in the lymphocytes—the infection-fighting cells. Lymphoma occurs when these lymphocytes change and grow out of control and interfere with the body’s healthy cells.

Healthy lymphocytes travel around the body in the lymphatic system, which is part of the germ-fighting network of the immune system. The lymphatic system runs throughout the body and includes lymph nodes (glands) and certain organs like the spleen and thymus. Lymphocytes collect in the lymph nodes, ready to fight infection. Lymph nodes are found throughout the body. With leukemia, the abnormal lymphocytes collect in the lymph nodes and can spread to other parts of the body and start growing there too.

Lymphoma can occur at any age. It is nearly always treatable, and most people live for many years after being diagnosed with lymphoma.

More information about lymphoma (National Cancer Institute).

What lymphoma is not

It’s important to know that lymphoma is not leukemia. Although both are blood cancers and their names sound similar, each cancer starts in a different type of cell. Lymphoma starts in infection-fighting lymphocytes, while leukemia starts in blood-forming cells inside bone marrow (the soft, spongy tissue that fills the center of bones).

Types of lymphoma

There are two main types of lymphoma:

  • Hodgkin Lymphoma: Most people with this disease have the classic type, which is characterized by the presence of large, abnormal lymphocytes (a type of white blood cell) in the lymph nodes called Reed-Sternberg cells. Hodgkin lymphoma can usually be cured.
  • Non-Hodgkin Lymphoma: Most people with lymphoma have this type. There are many types of Non-Hodgkin lymphoma, each with its own treatment and prognosis.

There are many types of lymphoma, and each can behave differently and need different treatments. Your doctor will help you understand what kind of lymphoma you have and discuss the right treatment plan for you.