NHL usually starts with an abnormal change in a white cell in a lymph node or lymphoid tissue called a lymphocyte. It can start in one of three major types of lymphocytes:
- B lymphocytes (B cells), which produce antibodies to help combat infections
- T lymphocytes (T cells), which have several functions, including helping B lymphocytes make antibodies
- Natural killer (NK) cells, which attack virus-infected cells or tumour cells
The abnormal lymphocyte grows out of control and produces more abnormal cells like it.
- These abnormal lymphocytes (lymphoma cells) accumulate and form masses (tumours).
- NHL that develops in or spreads to other areas of the body where lymphoid tissue is found, such as the spleen or the digestive tract is called extranodal lymphoma.
Some non-Hodgkin lymphomas grow slowly. These are called â€˜low-gradeâ€™ or â€˜indolentâ€™ lymphomas. Others grow more quickly. These are called â€˜high-gradeâ€™ or â€˜aggressiveâ€™ lymphomas. There are more than 30 types of non-Hodgkin lymphoma