Introduction to Lymphoma

Lymphoma, or lymphatic cancer, is a broad term encompassing a variety of cancers of the lymphatic system. The two main groups of lymphoma in humans are Hodgkin lymphoma (HL), also known as Hodgkin disease, and the non-Hodgkin lymphoma (NHL).

Hodgkin lymphoma, named for Thomas Hodgkin, a British physician who identified it in 1832, is a rare cancer and accounts for only about 14 percent of all lymphomas and less than 1 percent of all cases of cancer in this country.

In Hodgkin lymphoma, cells in the lymphatic system become abnormal. They divide too rapidly and grow without any order or control. Because lymphatic tissue is present in many parts of the body, Hodgkin lymphoma can start almost anywhere. Hodgkin lymphoma may occur in a single lymph node, a group of lymph nodes, or, sometimes, in other parts of the lymphatic system such as the bone marrow and spleen. This type of cancer tends to spread in a fairly orderly way from one group of lymph nodes to the next group. For example, Hodgkin lymphoma that arises in the lymph nodes in the neck spreads first to the nodes above the collarbones, and then to the lymph nodes under the arms and within the chest. Eventually, it can spread to almost any other part of the body (contiguous spread).

The other group, non-Hodgkin lymphoma, accounts for about 3 percent of all malignancies. In non-Hodgkin lymphoma, cells in the lymphatic system become abnormal. They divide and grow without any order or control, or old cells do not die as cells normally do. Because lymphatic tissue is present in many parts of the body, non-Hodgkin lymphoma can start almost anywhere in the body. Non-Hodgkin lymphoma may occur in a single lymph node, a group of lymph nodes, or in another organ. This type of cancer can spread to almost any part of the body, including the liver, bone marrow, and spleen (non-contiguous spread).