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Non-Hodgkin lymphoma is a cancer that starts in the lymphatic system, a network of blood vessels, blood cells, organs, and tissues that is part of the immune system, which fights infection. Lymphomas are cancers of the lymphocytes, a type of white blood cells.

Most lymphomas in children up to age 14 are non-Hodgkin lymphoma, while older teens are more likely to have Hodgkin lymphoma. The difference between the two lies in the type of lymphocyte present in the tumor. If the doctor finds cells called Reed–Sternberg cells, he or she classifies the cancer as Hodgkin lymphoma.

Almost all types of childhood non-Hodgkin lymphoma are aggressive, meaning the cancer grows quickly. More common in boys than in girls and in white children than in black children, non-Hodgkin lymphoma accounts for roughly 6 percent of all childhood cancers.

There are two main types of lymphocytes: B cells, which are designed to produce proteins called antibodies that fight infections, and T cells, which attack infections directly. Lymphocytes begin as immature cells, which can grow and develop to eventually become mature cells. In children, non-Hodgkin lymphoma typically starts in earlier developmental stages of B and T cells.

Doctors determine the type of non-Hodgkin lymphoma by the way the cancer cells look under a microscope and whether these cells are derived from B or T cells. The type of cell that’s affected determines the diagnosis and directs the course of treatment.

Pediatric hematologist–oncologists at the Stephen D. Hassenfeld Children’s Center for Cancer and Blood Disorders, part of Hassenfeld Children’s Hospital at ºÙºÙÊÓƵ, treat different types of childhood non-Hodgkin lymphoma.

B-cell Non-Hodgkin Lymphoma

B-cell lymphomas occur when B cells, one of the two types of lymphocytes, grow uncontrollably and become cancerous. It is the most common type of childhood non-Hodgkin lymphoma and includes two main types.

Diffuse Large B-cell Non-Hodgkin Lymphoma

Diffuse large B-cell non-Hodgkin lymphoma, a fast-growing form of non-Hodgkin lymphoma, can arise in many parts of the body, including the lymph nodes, bone marrow, brain, gastrointestinal tract, liver, spleen, testes, and thyroid gland. A rare subtype called primary mediastinal B-cell lymphoma produces a tumor between the lungs in the chest that can make breathing difficult.

Burkitt Lymphoma

Burkitt lymphoma, a fast-growing form of B-cell lymphoma, usually produces large tumors in the abdomen and spreads quickly to other organs. Burkitt lymphoma is caused by a translocation, or switching, of genes that makes them function incorrectly, leading to cancer. It can be associated with HIV and AIDS, Epstein–Barr virus, and malaria, and is most common in children, especially boys.

Burkitt lymphomas typically have a rearrangement of a gene called c-Myc. This means that a chromosome, a component of a person’s cells that carries genetic information, switches places with another chromosome.

Anaplastic Large Cell Lymphoma

Anaplastic large cell lymphoma, a fast-growing subtype of non-Hodgkin lymphoma, can appear in the lymph nodes and spread to the skin. It arises from T cells, and it may appear in the bones, liver, lungs, lymph nodes, skin, or soft tissue. Most of these types of non-Hodgkin lymphomas contain a chromosomal rearrangement of the anaplastic lymphoma kinase, or ALK, gene.

Lymphoblastic Lymphoma

Lymphoblastic lymphoma, a fast-growing type of non-Hodgkin lymphoma, typically starts in children in the lymph nodes and thymus, a gland behind the breastbone that helps the body make infection-fighting T cells. Children with this type of lymphoma often develop severe symptoms in a short period, just days to weeks.

Lymphoblastic lymphoma is more common in teenagers than young children and affects boys more often than girls. Most lymphoblastic lymphomas develop from T cells, and the remainder from B cells.