Hodgkin lymphoma is a cancer of the lymphatic system.
The lymphatic system is a system of thin tubes and lymph nodes that run throughout the body. Lymph nodes are bean shaped glands. The thin tubes are called lymph vessels or lymphatic vessels. Tissue fluid called lymph circulates around the body in these vessels and flows through the lymph nodes.
The lymph system is an important part of our immune system. It plays a role in fighting bacteria and other infections and destroying old or abnormal cells, such as cancer cells.
The diagram below shows parts of the lymphatic system.
Hodgkin lymphoma and non-Hodgkin lymphoma
There are 2 main types of lymphoma. They are called Hodgkin lymphoma and non-Hodgkin lymphoma.
Hodgkin lymphoma was named after the doctor who first recognised it. It used to be called Hodgkin's disease.
Hodgkin lymphomas have a particular appearance under a microscope. They contain cells called Reed Sternberg cells. Non-Hodgkin lymphomas look different under the microscope and do not contain Reed Sternberg cells.
Reed Sternberg cells are a type of white blood cell called a B lymphocyte, that has become cancerous. B lymphocytes normally make antibodies to help fight infections.
Most lymphomas are non-Hodgkin lymphoma. It's important for doctors to be able to tell the difference between Hodgkin and non-Hodgkin lymphomas. They are two different diseases and the treatment for them is not the same.
Where Hodgkin lymphoma can start
Hodgkin lymphoma can start anywhere in the lymphatic system. It can develop in more than one place in the body at the same time.
The most common place for it to be noticed is in the lymph nodes in the neck. But it can start in any of the lymph nodes in the body. For example; in the chest, groin, abdomen, or armpit.
You can also get Hodgkin lymphoma in body organs, such as in the liver, bone or lung.
Some people are diagnosed with Hodgkin lymphoma in their spleen. The spleen is a large organ to the left of your stomach. It is part of the lymphatic system and it helps to filter old or damaged blood cells and fights infection.
Hodgkin lymphoma can occur in either the tonsils or a gland in the chest called the thymus, but this is very rare. Lymphoma in these sites is usually non-Hodgkin lymphoma.
If Hodgkin lymphoma is in parts of the body outside the lymphatic system it is called extranodal disease.
Other types of cancer
Remember that it's very common for other types of cancer to spread to lymph nodes. This is not lymphoma. For example, breast cancer can spread to the lymph nodes close to the breast. This means the lymph nodes contain breast cancer cells not lymphoma cells.
For information about cancer that has spread to the lymph nodes you need to look at the section about your cancer type.
Who gets it
In the UK, Hodgkin lymphoma is slightly more common in males than females.
It can happen at any age. It's more common in young adults. It then becomes less common until middle age when it becomes more common again. There's a second peak in older age.
How common it is
Hodgkin lymphoma is rare. Around 2,100 people are diagnosed in the UK each year.