PREVIEWLymphoma is cancer that begins in infection-fighting cells of the immune system, called lymphocytes. These cells are in the lymph nodes, spleen, thymus, bone marrow, and other parts of the body. When you have lymphoma, lymphocytes change and grow out of control.There are two main types of lymphoma: Non-Hodgkin: Most people with lymphoma have this type.HodgkinNon-Hodgkin and Hodgkin lymphoma involve different types of lymphocyte cells. Every type of lymphoma grows at a different rate and responds differently to treatment.Lymphoma is very treatable, and the outlook can vary depending on the type of lymphoma and its stage. Your doctor can help you find the right treatment for your type and stage of the illness.Lymphoma is different from leukemia. Each of these cancers starts in a different type of cell.Lymphoma starts in infection-fighting lymphocytes.Leukemia starts in blood-forming cells inside bone marrow.Lymphoma is also not the same as lymphedema, which is a collection of fluid that forms in body tissues when there is damage or blockage to the lymph system