lymphoma in children | What is a child's Hodgkin's lymphoma?

What is a child's Hodgkin's lymphoma?

Hodgkin's lymphoma (LH) is a cancer that originates in lymphocytes. Lymphocytes are the cells of the lymphatic system.

The lymphatic system works together with other parts of your immune system to help your body defend against infections and diseases. It consists of a network of lymphatic vessels, lymph nodes and lymphatic organs. The vessels carry lymph that contains lymphocytes and other white blood cells as well as antibodies and nutrients. The lymph nodes, which are located along the lymphatic vessels, have the role of filtering the lymph. Lymphatic organs include spleen, thymus, tonsils, adenoids vegetation and bone marrow.

Lymphocytes develop in the bone marrow from base cells, or mother cells, called stem cells. These can produce different types of cells that have separate functions. Lymphocytes are a kind of white blood cells that help fight infections. There are two types:

B lymphocytes (B cells) that remain in the bone marrow until they reach maturity;
T lymphocytes (T cells) migrate to the thymus to further their development.
Lymphocytes sometimes undergo changes that make their mode of growth or their behavior abnormal. These abnormal cells can form tumors called lymphomas. Hodgkin's lymphoma usually takes birth in abnormal B lymphocytes called Hodgkin's and Reed Sternberg's cells, or HRS cells. These cells are much larger than normal B lymphocytes and they have a large nucleus or more than one nucleus.

Hodgkin lymphomas are divided into classical LH or nodular lh predominantly lymphocytic. Most of the LH in the child is classical.

The classical LH is characterized by the presence of the HRS cell. Who divides the classical LH into 4 subtypes.

LH Scléronodulaire is the most common type of Hodgkin's lymphoma in children. About half of all infant LH are scléronodulaires.
The LH with mixed cellularity represents about 30% of all LH in the child. This type of classical LH is more common in children under the age of 10.
Lymphocyte-rich LH accounts for about 5% of all LH in children.
Lymphocyte depletion LH is a very rare type of Hodgkin's lymphoma in children. It is aggressive, which means it can grow and spread quickly. This type of classical LH is usually observed in children infected with HIV or Epstein-Barr virus (EBV).
In the nodular predominantly lymphocytic LH, there is very little or no HRS cells at all. 10 – 15% of all LH in children are nodular predominantly lymphocytic. This type of infant LH is more common in children under the age of 10 and in boys under the age of 18.

Since lymphocytes are present throughout the lymphatic system, LH can manifest almost anywhere in the body. It usually appears in a group of lymph nodes of one part of the body, most often in the thorax, neck or armpits. LH usually propagates in a predictable and orderly manner, or from a group of lymph nodes to the neighbouring group. It can eventually spread to almost any body tissue or organ through the lymphatic system or blood circulation.

Other cancers of the lymphatic system are called non-Hodgkin lymphomas (NHL). Hodgkin's and Reed-Sternberg cells of Hodgkin's lymphoma have a different appearance and behaviour than non-Hodgkin's lymphoma cells. These two categories of lymphoma are treated differently.