Lymphomas are cancers of the lymphatic system, a key part of body’s immune system. The lymphatic system includes a series of olive-sized nodes that produce lymph, a fluid that carries disease-fighting white blood cells (known as lymphocytes) throughout the body, and the tubes that carry this fluid.
There are two types of lymphocytes affected by lymphoma: T cells and B cells, although B cell lymphomas are much more common.
There are several types of lymphoma, classified by how the cells appear under a microscope. In Hodgkin's lymphoma, the disease is defined by the presence of Reed Sternberg cells, which are large cells that can have more than one nucleus. These cells grow and divide more quickly and live longer than normal cells. They also produce substances that encourage more healthy cells to gather in the lymph nodes. These healthy cells themselves produce substances that encourage the growth of Reed Sternberg cells. There are several subtypes of Hodgkin’s Lymphoma, but the vast majority are classical Hodgkin's lymphoma.
Non-Hodgkin’s lymphoma (NHL), or simply lymphoma, does not have Reed Sternberg cells. There are several subtypes of NHL, including:
- Burkitt's Lymphoma (BL) affects B cell lymphocytes. It is one of the fastest-growing cancers.
- Lymphoblastic Lymphoma (LBL) mostly affects T cell lymphocytes and is similar to acute lymphoblastic leukemia (ALL). It makes up about one-third of all childhood NHL, and is more common in boys.
- Large Cell Lymphoma (LCL) includes two subtypes: diffuse large B-cell lymphoma (DLBCL) mostly affects pre-adolescent and teens; and anaplastic large cell lymphoma (ALCL) is more common in adolescents.
NHL is also classified by how fast it spreads. Nearly all cases of pediatric NHL are the aggressive form of the disease.
Childhood lymphoma risk factors
A risk factor is anything that increases the chances of a person developing a disease.
There are many different types of lymphoma, so not every risk factor applies to every type. In addition, most pediatric lymphoma patients don't have any of the risk factors listed here (other than race and gender). Nonetheless, the disease's risk factors include:
- Gender: Hodgkin's lymphoma is more predominant in males than females.
- Race: Whites are more likely to contract the disease than other groups.
- Infections including Epstein-Barr virus, which causes mononucleosis, and HIV
- Immune System diseases, including lupus and rheumatoid arthritis
- Immune deficiency syndromes, including:
- Bloom syndrome
- Common variable immunodeficiency
- Severe combined immunodeficiency syndrome (SCID)
- Wiskott-Aldrich syndrome
- Taking immunosuppressants due to organ transplant
- Having a parent or sibling with the disease
Some cases of lymphoma can be passed down from one generation to the next. Genetic counseling may be right for you. Learn more about the risk to you and your family on our genetic testing page.