Lymphoma is a cancer of the lymphatic system.
To help you understand it, it’s useful to know a bit about this system and what it does. The lymphatic system is part of the immune system. It helps to protect us from infection and disease and it drains fluid from the body’s tissues.
The lymphatic system is made up of:
- white blood cells, called lymphocytes
- lymphatic tissue, in the stomach, bowel, eye and thyroid gland
- lymphatic organs, such as the bone marrow, tonsils, thymus, testicles, spleen and lymph nodes.
The lymphatic system
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There are groups of lymph nodes throughout the body including in the neck, armpits, groin, chest and tummy area (abdomen). They are connected by a network of fine tubes called lymphatic vessels. Lymph nodes filter disease and germs (bacteria and viruses) from lymph, a liquid that travels through the lymphatic vessels. Lymph nodes often swell when they are fighting infection. You may have noticed this if you’ve ever had a throat infection and felt swollen ‘glands’ in your neck just below your jaw.
Lymph nodes contain lots of infection-fighting white blood cells, called lymphocytes. There are also some lymphocytes in the lymph and blood.
There are two main types of lymphocyte: B-cell lymphocytes and T-cell lymphocytes.
The bone marrow is a spongy material inside the bones. All the body’s blood cells, including lymphocytes, are made by special cells called stem cells inside the bone marrow.
Lymphoma is a cancer of the lymphatic system. Like other types of cancer, lymphoma is a disease of the body’s cells. The body is made up of cells that need to be replaced as they age or are damaged. This happens through cell division, which is when a cell divides and makes a new copy of itself.
Normally, cell division is carefully controlled so the right amount of cells are made to meet the body’s needs. However, if this process gets out of control for some reason, too many cells are made and a cancer can develop. In lymphoma, a lump or tumor forms in one or more groups of lymph nodes.
Because lymphocytes travel around the body, lymphoma can spread from where it first started. It can spread through the lymphatic system from lymph nodes in one part of the body to lymph nodes elsewhere. Lymphoma cells can also travel in the bloodstream to organs such as the bone marrow, liver or lungs. When the lymphoma cells reach a new area, they may carry on dividing and form a new tumor.
There are two main types of lymphoma:
- Hodgkin lymphoma (formerly known as Hodgkin’s disease)
- Non-Hodgkin lymphoma (formerly known as Non-Hodgkin’s lymphoma)
The difference between Hodgkin lymphoma and non-Hodgkin lymphoma
It’s only possible to tell the difference between Hodgkin lymphoma and non-Hodgkin lymphoma when the cells are looked at under a microscope.
In most cases of Hodgkin lymphoma, a particular cell called the Reed-Sternberg cell is found when cells from the lymph node are examined during diagnosis. This cell isn’t usually found in other types of lymphoma, so these types are called non-Hodgkin lymphoma.
This difference is important, because the treatment for Hodgkin and non-Hodgkin lymphoma can be very different. It’s thought that Reed-Sternberg cells are a type of white blood cell – a B-cell that has become cancerous. B-cells normally make antibodies to fight infection.