What is Lymphoma?

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.

What Causes Lymphoma?

The cause or causes of lymphoma are largely a mystery. There may be some genetic predisposition, or it may be caused by an environmental trigger such as pollution. There is not, however, sufficient evidence to provide a definitive answer. It has been shown that some NHLs of the digestive tract such as mucosa-associated lymphatic tissue (MALT) lymphomas may be caused by Helicobacter pylori infection. There also seems to be a link with Epstein-Barr virus and gene relocation in some forms of Burkitt’s lymphoma.

What is the Difference Between Hodgkin Lymphoma and Non-Hodgkin Lymphoma?

Lymphoma is an umbrella term used for over 50 related cancers. There are two general categories of lymphoma: Hodgkin and non-Hodgkin lymphoma (NHL).

The difference between Hodgkin lymphoma and NHL is the presence of Reed-Sternberg cells. A Reed-Sternberg cell is a cell derived from a B-lymphocyte and is only present in Hodgkin lymphoma. If Reed-Sternberg cells are present when the tumour is examined under a microscope, the diagnosis is Hodgkin lymphoma. If there are no Reed-Sternberg cells in a lymphatic tumour, the diagnosis is most likely to be NHL. NHL is more common than Hodgkin lymphoma, outnumbering it by a ratio of over six to one. Of all diagnosed lymphoma cases, 85% of them are NHL. Distinguishing between Hodgkin lymphoma and NHL is important to show different patterns of spread and that they require different treatments.

Find out more about the different types of lymphoma: