A lymphoma is a cancer of cells called lymphocytes - a type of white blood cell (see the lymphatic system for more info).
Normally lymphocytes grow and divide in an orderly way and are able to do their job of fighting 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.
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.
Just over 100 teenagers are diagnosed with Hodgkin in the UK each year (for those aged 20-24 the number is about 150 a year) and it affects both sexes equally.
