Lymphomas are cancers of lymphocytes, which reside in the lymphatic system and in blood-forming organs.

Lymphomas are cancers of a specific type of white blood cells known as lymphocytes. These cells help fight infections. Lymphomas can develop from either B or T lymphocytes. T lymphocytes are important in regulating the immune system and in fighting viral infections. B lymphocytes produce antibodies.

Lymphocytes move about to all parts of the body through the bloodstream and through a network of tubular channels called lymphatic vessels (see Biology of the Immune System: Lymphatic System: Helping Defend Against Infection). Scattered throughout the network of lymphatic vessels are lymph nodes, which house collections of lymphocytes. Lymphocytes that become cancerous (lymphoma cells) may remain confined to a single lymph node or may spread to the bone marrow, the spleen, or virtually any other organ.

The two major types of lymphoma are

• Hodgkin lymphoma (previously known as Hodgkin's disease)
• Non-Hodgkin lymphoma

Non-Hodgkin lymphomas are more common than Hodgkin lymphoma. Burkitt lymphoma and mycosis fungoides are subtypes of non-Hodgkin lymphoma.

Last full review/revision October 2012 by Carol S. Portlock, MD