Cancers arising from the lymph nodes or other sites of lymphoid tissue are broadly termed lymphomas . This group of diseases is divided into Hodgkin's disease and non-Hodgkin's lymphoma . In both conditions, there is a replacement of normal lymphatic tissue by collections of abnormal lymphoma cells. The lymphatic system is a complex network of specialised cells and organs that defend the body against infection. Lymphatic organs include the bone marrow, spleen, thymus gland, lymph nodes, tonsils, adenoids, appendix and clumps of tissue in the small bowel.
Cancerous changes can take place when mutation leads to failure of maturation of the lymphoid cells.
Lymphomas are therefore regarded as cancers of lymphocytes. The process by which lymphoma occurs consists of a series of events where normal lymphocyte cells cease to mature and develop in an orderly fashion. Typically, patients present with a painless swelling of lymph nodes, with or without fever, night sweats and weight loss. It is diagnosed in 7 per 100,000 people annually. Hodgkin's disease can occur at any age, but is rare in children.