The lymph system is made up of thin tubes that branch, like blood vessels, into all parts of the body. Lymph vessels carry lymph, a colorless, watery fluid that contains white blood cells called lymphocytes. Along the network of vessels are groups of small, bean-shaped organs called lymph nodes. Clusters of lymph nodes make and store infection-fighting cells.
The spleen (an organ in the upper abdomen that makes lymphocytes and filters old blood cells from the blood), the thymus (a small organ beneath the breastbone), and the tonsils (an organ in the throat), are also part of the lymph system.
Because there is lymph tissue in many parts of the body, the cancer can spread to almost any of the body’s organs or tissues including the liver, bone marrow (the spongy tissue inside the large bones of the body that makes blood cells), spleen, or brain.
More: What Is AIDS-Related Lymphoma?...................................................