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 are found in the underarm, pelvis, neck, and abdomen. The lymph nodes make and store infection-fighting cells. Because lymph tissue is found in many parts of the body, lymphoma can start in almost any part of the body.
Lymphoma can also occur in children and is treated differently.
Like all types of cancer, lymphomas affect the body's cells. Healthy cells grow, divide, and replace themselves in an orderly manner. This process keeps the body in good repair. In lymphoma, cells in the lymphatic system grow abnormally and can spread to other organs. As the disease progresses, the body is less able to fight infection.