Non-Hodgkin lymphoma, also known as NHL, is a type of cancer of the lymphatic system. There are two main types of lymphoma. One is called Hodgkin lymphoma, which used to be called Hodgkin's disease. The other is non-Hodgkin lymphoma.

About four in five (80%) of all lymphomas diagnosed are non-Hodgkin lymphoma. Over 9700 people in the UK are diagnosed with non-Hodgkin lymphoma each year.

The difference between NHL and Hodgkin lymphoma

It is only possible to tell the difference between Hodgkin and non-Hodgkin lymphomas, when the cells are looked at under the microscope. Often the cells need to be stained to show their structure in detail. Usually the cells will be tested for the presence of particular proteins – this is known as immunohistochemistry.

Another test, called molecular analysis, looks at specific gene changes in the cells. This also helps reveal the type of lymphoma.

In most cases of Hodgkin lymphoma, a particular cell known as the Reed-Sternberg cell is found in the biopsies. This cell is not usually found in other lymphomas, so they are called non-Hodgkin lymphoma. This may not seem a very big difference, but it is important because the treatments for Hodgkin and non-Hodgkin lymphomas are very different.

There are many different types of NHL, some of which are more common than others.