Lymphoma is a type of cancer that begins in the lymphatic system, a crucial part of the immune system that protects the body against diseases and infections. This system includes a network of vessels that transport a clear fluid called lymph, as well as organs like the spleen, thymus, and bone marrow.
Lymph contains white blood cells known as lymphocytes, which produce antibodies to fight bacteria and viruses. There are two main types of lymphocytes: B-lymphocytes and T-lymphocytes. These cells are essential in defending the body against infections by producing antibodies and attacking harmful organisms.
Lymphoma occurs when lymphocytes grow abnormally and accumulate, forming a lump or tumor. While this usually happens in the lymph nodes, it can also occur in other parts of the body.
There are over 80 sub-types of lymphoma, generally classified as Hodgkin lymphoma or Non-Hodgkin lymphoma. These sub-types are further categorized based on whether they affect B-lymphocytes or T-lymphocytes, and whether they are slow-growing (indolent) or fast-growing (aggressive). About 85% of lymphomas affect B-lymphocytes.