Hodgkin lymphoma is a cancer of the lymphatic system – part of the body’s immune system. There are two main types of lymphoma: Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Only about 1 in 5 of all lymphomas diagnosed (20%) are Hodgkin lymphoma.
How does Hodgkin lymphoma develop?
Hodgkin lymphoma, like all cancers, is a disease of the body’s cells. Cells are tiny building blocks that make up the organs and tissues of our bodies. They divide to make new cells in a controlled way. This is how our bodies grow, heal, and repair.
Cells receive signals from the body telling them when to divide and grow and when to stop growing. When a cell is no longer needed or can’t be repaired, it gets a signal to stop working and die. Cancer develops when the normal workings of a cell go wrong and the cell becomes abnormal. The abnormal cell keeps dividing making more and more abnormal cells.
In Hodgkin lymphoma, blood cells called lymphocytes become abnormal. These abnormal lymphocytes (lymphoma cells) keep dividing and grow out of the body’s control. Over time, the number of lymphoma cells increases and they form a lump called a tumor.
Lymphoma cells generally start to grow in lymph nodes. As there are lymph nodes and lymph vessels throughout the body, Hodgkin lymphoma can start in any part of the body. The most common place for it to start is in the lymph nodes in the neck. The next most common places are the lymph nodes:
- under the arms (axilla)
- in the chest
- in the groin
Hodgkin lymphoma may affect a group of lymph nodes in just one area of the body. However, it’s common for lymphoma to be found in lymph nodes in more than one area of the body. This is because lymphoma cells can sometimes spread through the lymphatic system.
Lymphoma cells can also spread to other organs in the bloodstream. When the cells reach a new area, they may go on dividing and form a new tumor. Hodgkin lymphoma can also occur in body organs. In some people it can affect the spleen, liver, lungs or bone marrow.
The treatment of Hodgkin lymphoma is usually very successful, even when it is in several different areas of the body. Most people can now be cured or the lymphoma can be controlled for many years.
There are different types of Hodgkin lymphoma. It’s grouped using the World Health Organization’s (WHO) lymphoma classification system:
Classical types
These are the most common types of Hodgkin lymphoma. There are four subtypes:
- Nodular sclerosing
- Mixed cellularity
- Lymphocyte-depleted
- Lymphocyte-rich.
Nodular lymphocyte-predominant type
This is a rare type of Hodgkin lymphoma. About 5% of all Hodgkin lymphomas diagnosed are this type.
Your doctors can tell which type you have by examining the cells under the microscope.