Lymphoma is cancer that begins in infection-fighting cells of the immune system, called lymphocytes. This type of cancer begins in the lymph nodes and other lymphatic tissue. The tumorous cells spread to the rest of the body, forming nodules or tumors. There are different types of lymphoma, and each type has many subtypes.

Hodgkin lymphoma (HL) is the most common type of lymphoma. It begins in the lymph nodes, which are small organs that collect white blood cells, the army of soldiers in our immune system. The cancerous cells start in the swollen parts of the lymph nodes or in the tissue covering them. The cancerous cells spread to other lymph nodes or to other parts of the body. There are different grades of HL based on how large and how fast they grow after they start growing. In some cases, a grade 3 tumor may appear over time without any signs or symptoms to show that it is growing and spreading.

Non-Hodgkin lymphoma (NHL) is less common than HL but can be just as deadly. It begins in lymphocytes or other immune system cells in the body, including B cells and T cells (which fight infection), and plasma cells (which make antibodies to fight infection). The most common types of NHL are:

Mantle Cell Lymphoma is a rare type of NHL. Cancer begins in lymphocytes and typically starts in the neck, armpit, or chest. It is more common in older men over 50 years of age who are non-smokers and have a weakened immune system and no other health problems that weaken the immune system.

Diffuse Large B-Cell Lymphoma (DLBCL) accounts for about 25% of NHL cases in adults and 60% of all NHL cases in adolescents and young adults under age 30 years old. It is the most common type of NHL that affects adolescents under the age of 15 years old.

Follicular Lymphoma is the second most common type of NHL in adults, usually beginning in the skin, lymph nodes, or other organs like the spleen and liver.

Acute Lymphocytic Leukemia (ALL) is the most common leukemia in children under 10 years old and teens between 10 and 20 years old. It begins in B cells, which are a type of white blood cell that makes antibodies to fight infection. In ALL, the cancerous white blood cells grow faster than normal blood cells, crowding out other blood cells in the marrow. It is also known as acute lymphoblastic leukemia (ALL).

Chronic Lymphocytic Leukemia (CLL) is a cancer of B cells. The cancerous B cells grow more slowly than they do in ALL and crowd out other blood cells in the marrow. It accounts for about 20% of adult NHL cases and most often can be found in older men and women, most commonly over age 50 years old.

Each type of lymphoma and leukemia can involve many other systems and organs, including the central nervous system, kidneys, and liver. Lymphoma is a very complex type of cancer with many types. The type of lymphoma or leukemia depends on what kind of cell cancer began and where the cancer started.