Lymphomas are cancers of the lymphatic system
When you have lymphoma, some of your lymphocytes (specialised white blood cells that normally fight infection) are ‘out of control’. They divide in an abnormal way, or do not die when they should. These abnormal lymphocytes can collect in the lymph nodes, which are small oval swellings arranged in groups at various points along the course of the lymphatic drainage system.
Lymphoma can affect lymph nodes in all parts of your body. It can also involve other organs, such as the spleen (part of the immune system) or your bone marrow.
Like other cancers, lymphoma can affect the function of the tissue involved. For example, if the lymphoma is in your bone marrow (where your blood is made) you might not be able to make new blood cells.
Although lymphoma is a disease of the lymphatic system, it can also arise in other parts of your body. For example, lymphoma can affect your breast, stomach, bowel, skin or liver. Lymphoma that occurs in areas such as these is said to be ‘extranodal’, meaning ‘outside of lymph nodes’.