NCCN Guidelines for Patients® | Diffuse Large B-cell Lymphoma

8 NCCN Guidelines for Patients ® : Diffuse Large B-cell Lymphoma, 2017 1 DLBCL basics Lymphatic system | A disease of cells You’ve learned that you have or may have lymphoma. It’s common to feel shocked and confused. Part 1 reviews some basics that may help you learn about DLBCL. Lymphatic system Before learning about DLBCL ( d iffuse l arge B - c ell l ymphoma), it is helpful to know about the lymphatic system. It is one of 13 systems of the human body. It transports fluids to the bloodstream and fights germs. As such, it supports your blood-flowing (cardiovascular) and disease-fighting (immune) systems. Lymph Cells are the building blocks of tissue in the body. The spaces between cells are filled with fluid. This fluid is called interstitial or tissue fluid. Most tissue fluid comes from parts of blood plasma that have passed out of blood vessels. Cells also release waste and other products into tissue fluid. When tissue fluid increases, it drains into vessels. Almost all of tissue fluid drains back into blood vessels. The rest of it drains into lymph vessels. Once inside of lymph vessels, tissue fluid is called lymph. Lymph travels in lymph vessels back to the bloodstream. The lymphatic system also collects fat and some vitamins from your gut. After you eat, your stomach turns food into a liquid. Then, the liquid drains into your small intestine. Within your small intestine, fat and some vitamins are absorbed into lymph vessels. This fatty lymph, called chyle, travels in lymph vessels to the bloodstream. Lymphoid tissues As lymph travels, it will pass through and be filtered by lymph nodes. Lymph nodes are organized masses of lymphoid tissue. There are hundreds of lymph nodes throughout your body. See Figure 1 . High numbers of lymph nodes exist in the middle of your chest, neck, armpit, groin, pelvis, and along your gut. Lymph nodes and other lymphoid tissue are defined by high numbers of lymphocytes. Lymph also has lymphocytes. Lymphocytes are a type of white blood cell. They help fight germs. The three types of lymphocytes are NK ( n atural k iller) cells, B-cells, and T-cells. Lymphocytes are made in bone marrow then are moved by blood to the lymphatic system. Other parts of your body that have many lymphocytes are included in the lymphatic system. In children, the thymus stores T-cells until they are able to fight germs. Germs in blood are filtered and destroyed by lymphocytes within your spleen. Your tonsils kill germs in lymph that enter through your mouth and nose. There are also small clumps of lymphatic tissue in your gut, thyroid, breasts, lungs, eyes, and skin. A disease of cells Your body is made of trillions of cells. Cancer is a disease of cells. Each type of cancer is named after the cell from which it derived. Lymphoma Lymphomas are cancers of lymphocytes within the lymphatic system. There are two main types of lymphomas. Hodgkin lymphoma is defined by the presence of Reed-Sternberg or related cells. Non- Hodgkin’s lymphomas include all the other types of lymphomas.