hodgkin's lymphoma | What is Hodgkin's lymphoma?

What is Hodgkin's lymphoma?

Cancer originates when cells begin to grow uncontrollably. Almost any cell in the body can become cancer and then spread to other parts of the body. For more information on the origin and spread of cancers, see what is cancer?

Lymphomas are cancers that begin in white blood cells called lymphocytes. There are two main types of lymphoma:

Hodgkin's lymphoma (HL)
Non-Hodgkin's lymphoma (NHL)
The two types of lymphoma behave, propagate, and respond to treatment in a different way. So it's important to know what type you have.

This article discusses Hodgkin lymphoma. For information on the other type, see non-Hodgkin's lymphoma.

The lymphatic system
To understand what Hodgkin lymphoma is, it is useful to know about the lymphatic system. The lymphatic system is part of the immune system that helps fight infections and some other illnesses. It also helps to control fluid circulation in the body.

The lymphatic system is mainly composed of cells called lymphocytes, a type of white blood cell. There are 2 main types of lymphocytes:

B lymphocytes (b cells): B cells produce proteins called antibodies to help protect the body from germs (bacteria and viruses)
T-lymphocytes (T cells): There are many types of T cells. Some T-cells destroy germs or abnormal cells in the body. Other T-cells stimulate or slow the activity of other immune system cells.
Hodgkin's lymphoma usually starts in B lymphocytes.

Onset and propagation of Hodgkin's lymphoma
Lymphatic tissue is found in many parts of the body, so Hodgkin's lymphoma can originate in almost all parts of the body.

The main lymphatic tissue locations are:

Lymph nodes: Lymph nodes are groups of lymphocytes and other immune system cells that have the form of a bean. These are found throughout the body, including within the thorax, abdomen (belly), and pelvis. The lymph nodes are connected to each other by a system of lymphatic vessels.

Lymphatic vessels: A network of tiny tubes (very similar to blood vessels) that connect to the lymph nodes and carry immune cells in a clear fluid called lymph.  The lymph is obtained from the whole body and passes into the bloodstream.

Spleen--The spleen is an organ found under the lower ribs on its left side. The spleen is part of the immune system, and it produces lymphocytes and other cells in this system. It also stores healthy blood cells and serves as a filter to remove damaged cells from blood, bacteria and cellular debris.

Bone marrow: The bone marrow is the spongy and liquid tissue found inside certain bones. New blood cells (including some lymphocytes) occur in the bone marrow.

Thymus: The thymus is a small organ that lies behind the upper part of the sternum and in front of the heart. This organ is important for the development of T lymphocytes.

Adenoids and tonsils: These are conglomerates of lymphatic tissue at the back of your throat. Both help to produce antibodies to germs that are inhaled or swallowed.

Digestive tract: The stomach, intestines, as well as many other organs, also contain lymphatic tissue.

Although Hodgkin's lymphoma can begin anywhere, it is most often originated in the upper body's lymph nodes. The most frequent locations are the thorax, neck, or under the arms.

More often, Hodgkin's lymphoma is propagated by lymph node-to-ganglion vessels. Rarely, during the advanced stage of the disease, it can invade the bloodstream and spread to other parts of the body, such as the liver, lungs, and/or bone marrow.

Types of Hodgkin's lymphoma
Different types of Hodgkin's lymphoma can grow and spread in a different way and can be treated differently.

Hodgkin's lymphoma, classic

Classical Hodgkin lymphoma (CHL) represents more than 9 of 10 cases of Hodgkin lymphoma in developed countries.

The cancerous cells in the CHL are called Reed-Sternberg cells. Usually these cells are an abnormal type of B lymphocytes. Enlarged lymph nodes in people with CHL usually have a small number of Reed-Sternberg cells with many surrounding normal immune cells. These other immune cells cause most of the swelling in the lymph nodes.

Classical Hodgkin lymphoma has four subtypes:

Hodgkin's lymphoma with Nodular sclerosis: This is the most common type of Hodgkin's disease in developed countries. It is responsible for approximately 7 out of 10 cases. It is more common in adolescents and young adults, although it may occur in people of any age. It tends to originate in the lymph nodes of the neck or thorax.

Hodgkin's lymphoma with mixed cellularity: This is the second most common type, found in about 4 to 10 cases is observed mainly in people with HIV infection. It also affects children or the elderly. It may originate in any lymph node, although it occurs more often in the upper half of the body.

Hodgkin's lymphoma with predominance lymphocyte: This subtype is not common. It usually occurs in the upper half of the body, and is rarely found in more than a few lymph nodes.

Hodgkin's lymphoma with depletion lymphocyte: It is an uncommon form of Hodgkin's disease. It is seen primarily in older people and those with HIV infection. It is more aggressive than other types of Hodgkin's lymphoma and is likely to be in advanced stage at the time of Detection. It is very likely to affect the lymph nodes in the abdomen, spleen, liver, and bone marrow.

Hodgkin's lymphoma with nodular lymphocyte predominance

Hodgkin's lymphoma with nodular lymphocyte predominance (NLPHL) represents about 5% of the cases. The cancer cells in the NLPHL are large, called popcorn cells (as they look like popcorn), which are variants of Reed-Sternberg cells. It is also possible that these cells are called lymphocytic cells and Histiocíticas (L & H).

NLPHL usually originates from the lymph nodes in the neck and under the arm. It may be present in people of any age, and is more common in men than in women. This type of Hodgkin's lymphoma tends to grow faster and treatment is different from that used for classic types.