Lymphoma is a cancer of the lymphatic system. In lymphoma a tumour develops due to abnormal and out-of-control growth of abnormal lymphocytes. Because the lymphatic system exists throughout the body and involves many organs, there may be cancerous tumours in many parts of the body. Lymphoma encompasses a variety of cancers specific to the lymphatic system, an important network of glands and vessels that make up the body’s immune system, our main line of defense against disease. There are two main categories of lymphoma: Hodgkin and non-Hodgkin (NHL).
The lymphatic system manufactures and circulates lymph throughout the body. Lymph is a clear, watery fluid that contains lymphocytes, white blood cells that fight infection and disease. Along the network are bean-shaped organs called lymph nodes or glands. The nodes are responsible for the manufacture and storage of these infection-fighting cells. Lymph nodes are clustered in the neck, armpits, in the groin and abdomen and may swell and become tender when the body is fighting infection (such as occurs in mononucelosis or strep throat).
When lymphoma occurs, some of the cells in the lymphatic system grow abnormally and out of control. Eventually, they may form a tumour that continues to grow as the cancerous cells reproduce. If all the cells are the same, they are called malignant or cancerous, because they will continue to grow and eventually harm the body’s systems. Because there is lymph tissue throughout the body, the cancer cells may spread to other organs, or even into the bone.