A lymphoma is a cancer of cells called lymphocytes, a type of white blood cell. See the lymphatic system for more information.
Normally lymphocytes grow and divide in an orderly way and are able to do their job (fight infection and disease). But when a lymphoma develops, a change has happened which means that the cells aren't able to do this and the process gets out of control. The cells continue to divide, so there are too many cells which haven't matured (and aren't able to do their job) in the blood and the bone marrow. The lymphoma cells may then lodge in the system and form lumps, which is why one of the first symptoms people experience is often a lump in their neck, armpit or groin, although this could happen in any part of the system.
There are two main types:
- Hodgkin lymphoma (used to be called Hodgkin's disease or Hodgkin's lymphoma). The name comes from a Dr Thomas Hodgkin, who first described the condition in the 1800s.
- non-Hodgkin lymphoma (NHL)
Although both these cancers are lymphomas, they are different and need different treatments, so it's important for doctors to tell whether you have the Hodgkin or non-Hodgkin type. Hodgkin lymphoma has something called Reed-Sternberg cells. These can be seen under a microscope and aren't present in non-Hodgkin lymphoma.
There are over 20 different types of NHL; each looks different under the microscope and needs different treatment. You will probably be told that you have one of two main groups either:
- B-cell NHL or
- T-cell NHL. (This is the more common type to be diagnosed with as a teenager or young person.)
Although it is a cancer of the lymphatic system, because the lymphoma cells travel through this system and in the bloodstream, they can affect other organs such as the lungs or the stomach. This condition is called extranodal lymphoma.
