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What is Childhood Lymphoma?
Lymphoma is the third most common cancer in children, after brain tumors and leukemia. Lymphoma begins in the lymphocytes, which are normal cells that are a part of the immune system. These normal cells are transported throughout the body by the lymphatics, a system of small vessels usually found close to normal blood vessels. Lymph nodes are normal small collections of lymphocytes that are found in the center of the chest, under the arms, in the neck, in the abdomen and in the groin. These nodes are connected by means of the lymphatics, small channels that connect the lymph nodes, and lymphocytes are free to move through these channels. They are also capable of moving throughout the body via the blood and can be found in many normal organs, including the bone marrow, spleen, thymus and digestive tract.
Lymphoma develops when lymphocytes undergo genetic mutations that cause them to grow uncontrollably.There are two broad categories of lymphomas: Hodgkin lymphoma and Non-Hodgkin lymphoma. Both types are cancers that develop in lymph nodes, and have the potential to start growing and spread to other nodes or normal tissues. In general, Hodgkin lymphoma and non-Hodgkin lymphoma behave quite differently in children.
Hodgkin Lymphoma in Children
Hodgkin lymphoma develops from B lymphocytes, a type of white blood cell that normally produces antibodies that fight infection. The cancerous lymphocytes of Hodgkin lymphoma are called Reed-Sternberg cells, which look and behave differently than do normal lymphocytes and non-Hodgkin lymphoma cells. Hodgkin lymphoma most commonly affects teenagers and adolescents over the age of 15. Here are the most common sub-types of Hodgkin lymphoma in children:
Collapsed Types of Hodgkin Lymphoma
Nodular Sclerosing Hodgkin Lymphoma
This type of classical Hodgkin lymphoma often begins in the lymph nodes in the neck or chest, and may spread to the lungs. People of any age may develop Nodular Sclerosing Hodgkin Lymphoma, but it is the most common form of childhood Hodgkin lymphoma and develops mostly in adolescents and young adults.
Mixed Cellularity Hodgkin Lymphoma
Mixed cellularity Hodgkin lymphoma usually begins in lymph nodes in the upper half of the body and contains a mixture of Reed-Sternberg cells, normal lymphocytes and several other types of normal cells. Children with mixed cellularity Hodgkin lymphoma are usually under the age of 10. This form of lymphoma is strongly linked to the Epstein-Barr Virus.
Nodular Lymphocyte Predominant Hodgkin Lymphoma
This form of Hodgkin lymphoma may begin in lymph nodes in the neck, underarms, or groin, though it most commonly arises in the neck and underarm lymph nodes. It and contains “popcorn cells,” which are a type of Reed-Sternberg cell. It is more common in younger, male patients. It is typically, more indolent that those above, and treatment might be slightly different.
Non-Hodgkin Lymphoma in Children
Non-Hodgkin lymphoma may develop from B lymphocytes or T lymphocytes, although B lymphocyte lymphomas are more common. Non-Hodgkin lymphoma may affect children at a younger age than Hodgkin lymphoma. Non-Hodgkin lymphomas in children are generally very aggressive and grow quickly. Here are the most common sub-types of Non-Hodgkin lymphoma in children:
Collapsed Types of Non-Hodgkin Lymphoma
Burkitt Lymphoma
Burkitt lymphoma is an aggressive, fast-growing lymphoma. In children, this disease is most common in boys between the ages of 5 and 10. Burkitt lymphoma often starts in the abdomen, and it is the most common bowel tumor in children. It can block the intestines, causing stomach pain, nausea, and constipation. This lymphoma often involves more than just nodes, and without proper therapy can spread to the brain, spinal cord, bone marrow, or other organs. Despite its aggressive nature, if diagnosed on time, it is one of the most curable childhood diseases.
Lymphoblastic Lymphoma
Lymphoblastic Lymphoma: Lymphoblastic lymphoma is a rare but aggressive disease. Lymphoblastic lymphoma (LBL) usually develops from very young T or B lymphocytes called lymphoblasts, which are very similar to cells seen in T-Acute Lymphoblastic Leukemia or B-Acute Lymphoblastic Leukemia (ALL). T-LBL is more common than B-LBL. Additionally, the disease is considered ALL instead of LBL if more than or equal to 20% of the bone marrow is made up of lymphoblasts. This disease mainly affects teenagers and young adults and often develops in the thymus, an organ found in the chest. Lymphoblastic lymphomas may form a mass in the chest and cause difficulty breathing. This disease spreads quickly and may spread to the bone marrow, other lymph nodes, the surface of the brain, or the membrane around the lungs and heart. The treatment is almost identical to that of ALL.
Large Cell Lymphoma
Large cell lymphomas may start in B lymphocytes or T lymphocytes anywhere in the body. Large cell lymphomas are less aggressive and less likely to spread than other forms of childhood lymphoma. Large cell lymphomas tend to affect older children and teenagers. There are two main types of large cell lymphoma:
- Diffuse Large B-Cell Lymphoma: Diffuse large B-cell lymphoma is a moderately aggressive disease that accounts for about 15% of all childhood lymphomas. This disease usually starts in a lymph node, but about half of all patients have involvement of other sites at the time of diagnosis. This disease often grows in large masses in the space between the lungs, but it may also be found in other places such as the neck, abdomen, or bones.
- Anaplastic Large Cell Lymphoma: Anaplastic large cell lymphoma accounts for about 10% of all non-Hodgkin lymphoma diagnoses in children. It develops from mature T cells and mainly affects children and adolescents. Anaplastic lymphoma often begins in lymph nodes in the neck, but may also start in lymph nodes in another part of the body. It can often be found in the skin, lungs, bones, gastrointestinal tract or other organs.
