In non-Hodgkin lymphoma (NHL), blood cells called lymphocytes become abnormal. Over time there are enough lymphoma cells to make a lump, called a tumour.
Non-Hodgkin lymphoma (NHL), like other types of cancer, is a disease of the cells in the body.
The body is made up of cells that need to be replaced as they age or are damaged. This happens by cell division, which is when a cell divides and makes new copies of itself.
Normally, cell division is carefully controlled. But sometimes this process can get out of control. Too many cells may be made and a cancer, such as lymphoma, can develop.
In NHL, blood cells called lymphocytes become abnormal. These abnormal lymphocytes are the lymphoma cells. They keep dividing and grow out of the body’s control. Over time, there are enough lymphoma cells to make a lump, called a tumour.
The most common place for this to happen is in the lymph nodes. But NHL can start in almost any part of the body, including the stomach, small bowel, skin, tonsils, thyroid or testicles. Lymphoma that grows outside the lymph nodes is called extra-nodal lymphoma.
Lymphocytes travel around the body, so NHL can spread from where it first started. The lymphoma cells can move 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. They may then carry on dividing and make another tumour.