What is Hodgkin lymphoma?
Hodgkin lymphoma is a type of blood cancer that affects 
called . It is also called 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. Lymphocytes circulate around the body in these vessels and through lymph nodes in a clear fluid called lymph. The lymphatic system is made up of several different organs, including the bone marrow, the spleen and the thymus gland.
The lymphatic system is an important part of our immune system. It plays a role in fighting bacteria and other infections. And it destroys old or abnormal cells, such as cancer cells. Lymph nodes commonly swell if we have an infection, such as a cold. But they usually go back to normal after a short time. Hodgkin lymphoma can cause your lymph nodes to swell, talk to your GP if you have swollen lymph nodes that keep getting bigger, or don’t go down.
The diagram below shows the lymph vessels, lymph nodes and the organs that make up 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 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 different diseases and the treatment for them is not the same.
This video explains what lymphoma is and how it starts. And the difference between Hodgkin lymphoma and non-Hodgkin lymphoma. The video lasts just over 3 minutes.
What is lymphoma?
Lymphoma is cancer of the lymphatic system.
There are two main types: Hodgkin lymphoma and non-Hodgkin lymphoma - or NHL.
The lymphatic system is part of our immune system it helps us fight infections.
Understanding how it works may help you to understand what lymphoma is.
The lymphatic system is made up of a number of different organs, including the bone marrow, the spleen and the thymus gland.
It’s also made up of thin tubes and lymph nodes which contain lymph fluid.
Lymph nodes are sometimes called lymph glands.
The lymphatic system runs throughout the body.
The lymph nodes filter substances that travel in the lymph fluid.
They also contain lymphocytes, a type of white blood cell that helps us to fight infections.
There are two main types of lymphocytes: B cells and T cells.
They work in slightly different ways.
A lymphoma starts when the lymphocytes become abnormal.
The abnormal cells make more abnormal cells, which means you have many more lymphocytes than usual, but they can’t fight infections as well as they should.
These abnormal cells circulate around the lymphatic system and start to build up in the lymph nodes forming a lump.
You may notice swollen glands in your neck, your armpit, or your groin.
But they can collect in other parts of your body that you can’t feel, including your lungs, liver and spleen.
It's important that your doctor finds out which type of lymphoma you have – Hodgkin lymphoma or non-Hodgkin lymphoma as they are two different diseases.
The most common type of Hodgkin lymphoma is called classical Hodgkin lymphoma.
It starts in B cells and contains Reed-Sternberg cells.
So, finding out if these particular cells are present confirms it's this type of lymphoma.
Non-Hodgkin lymphomas are the more common type of lymphoma.
There are many different types of non-Hodgkin lymphomas and they are grouped into either high grade or low grade.
High grade are faster growing and low grade NHL’s grow more slowly.
Your doctor will tell you the type of lymphoma you have and what this means for you.
It depends on the type of lymphoma you have as to what treatment you need.
You might have drug treatment, radiotherapy, or a stem cell transplant.
For more information about lymphoma, the tests you might have, and treatments visit cruk.org/ about-cancer/lymphoma
Where Hodgkin lymphoma can start
Because the lymphatic system runs through your whole body, Hodgkin lymphoma can start anywhere. It can also develop in more than one place in the body at the same time.
The most common place to notice it is in the lymph nodes in the neck. But it can start in any of the lymph nodes in the body, such as:
- the centre of the chest, called the
mediastinum - armpit (axilla)
- tummy (abdomen)
- groin
Hodgkin lymphoma in organs
You can also get Hodgkin lymphoma in body organs, such as the lungs, bones or liver. This is known as extranodal disease.
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.
How does Hodgkin lymphoma affect the body?
When you have Hodgkin lymphoma, some of your white blood cells (B lymphocytes) become abnormal and multiply. You then have more lymphocytes than usual, but they can’t fight infections as well as they should.
The cells can then clump together usually within lymph nodes or other parts of the lymphatic system to form tumours. This can cause problems in the lymphatic system and the part of the body where they are growing. For example, if Hodgkin lymphoma is in the chest, the enlarged lymph nodes can compress the airway and cause shortness of breath, coughing and discomfort.
Other cancers that have spread to the lymph nodes
Remember that it's very common for other types of cancer to spread to lymph nodes. This is not lymphoma. Lymphoma is cancer that starts in the lymphatic system.
For example, if breast cancer spreads to the lymph nodes in the armpits it does not become lymphoma. The cancer cells that have spread to the lymph nodes are still breast cancer cells. So they are treated as breast cancer.
If your cancer has spread to the lymph nodes (and is not lymphoma), you should look at information about that type of cancer.
Who gets it
Hodgkin lymphoma can happen at any age. In the UK it is more common between the ages of 20 and 24 and between 75 and 79 years old. In the UK, Hodgkin lymphoma is slightly more common in men than women.
How common is Hodgkin lymphoma
Hodgkin lymphoma is not one of the common cancers in the UK. Around 2,100 people are diagnosed in the UK each year.
