Lymphomas are most often classified by how the cancer cells look under the microscope. Key features include the size and shape of the cells and how they are arranged (their pattern of growth).
- Size is described as large or small.
- Shape is described as cleaved (showing folds or indentations) or non-cleaved.
- The growth pattern may be either diffuse (cancer cells are scattered) or follicular (cells are arranged in clusters).
Not every lymphoma is described using all 3 features (size, shape, and growth pattern). Special lab tests are often needed to accurately classify lymphomas. These are discussed in the section, “How is non-Hodgkin lymphoma diagnosed in children?”
The most common types of non-Hodgkin lymphoma (NHL) in children are different from those in adults. Nearly all NHLs in children belong to 1 of 3 main types:
- Lymphoblastic lymphoma
- Burkitt lymphoma (small non-cleaved cell lymphoma)
- Large cell lymphoma
All 3 types are high grade (meaning they grow quickly) and diffuse, but it is important to distinguish among them because they are treated differently.
There are many other types of NHL. These are much more common in adults and are rare in children, so they are not discussed further in this document.
Lymphoblastic lymphoma accounts for about 25% to 30% of NHL in children. It is most common in teens, and boys are affected about twice as often as girls.
The cancer cells of this lymphoma are very young lymphocytes called lymphoblasts. They are the same cells as those seen in acute lymphoblastic leukemia (ALL) in children. In fact, if more than 25% of the bone marrow is made up of lymphoblasts, the disease is classified and treated as ALL instead of lymphoma.
Most cases of lymphoblastic lymphoma develop from T cells and are called precursor T-lymphoblastic lymphomas. These lymphomas often start in the thymus, forming a mass in the area behind the breast bone and in front of the trachea (windpipe). This can cause problems breathing, which may be the first symptom of lymphoblastic lymphoma.
Less often, this cancer develops in the tonsils, lymph nodes of the neck, or other lymph nodes. It can spread very quickly to the bone marrow, other lymph nodes, the surface of the brain, and/or the membranes that surround the lungs and heart.
A small fraction of lymphoblastic lymphomas develop from B cells (called precursor B-lymphoblastic lymphomas). These lymphomas more often begin in lymph nodes outside the chest, particularly in the neck. They can also involve the skin and bones.
Lymphoblastic lymphoma can grow very quickly and can often interfere with breathing, so it needs to be diagnosed and treated quickly.
Burkitt lymphoma, also known as small non-cleaved cell lymphoma, accounts for about 40% of childhood NHL in the United States. It is most often seen in boys, usually when they are around 5 to 10 years old.
A subtype of Burkitt lymphoma, sometimes called Burkitt-like lymphoma or non-Burkitt lymphoma, shares some features with diffuse large B-cell lymphoma (described below) when seen under the microscope, but it is still treated like Burkitt lymphoma.
Burkitt lymphoma is named after the doctor who first described it in African children. In certain parts of Africa, Burkitt lymphoma accounts for nearly all childhood NHL and over half of all childhood cancers. In African children this lymphoma usually develops in the jaw or other facial bones.
Burkitt lymphomas in other parts of the world, including the United States, almost always start in the abdomen (belly). Typically, a child will develop a large tumor in his or her abdomen that can sometimes block the bowels (intestines). This can cause belly pain, nausea, and vomiting. Burkitt lymphoma can also sometimes start in the neck or tonsils, or rarely in other parts of the body.
This lymphoma develops from B lymphocytes, and it is one of the fastest growing cancers known. It can spread to other organs, including the surface of the brain or inside the brain. Because of this, it must be diagnosed and treated quickly.
Large cell lymphomas
These lymphomas start in more mature forms of T cells or B cells and can grow almost anywhere in the body. They are not as likely to spread to the bone marrow or brain, nor do they grow as quickly as other childhood lymphomas. These lymphomas tend to occur more often in older children and teens. There are 2 main subtypes of large cell lymphoma.
Anaplastic large cell lymphoma (ALCL): This lymphoma represents about 10% of all NHL in children. It usually develops from mature T cells. It may start in lymph nodes in the neck or other areas, and may be found in the skin, lungs, bone, digestive tract, or other organs.
Diffuse large B-cell lymphoma: This lymphoma accounts for about 15% of childhood lymphomas. It starts in B cells, as the name implies. These lymphomas often grow as large masses in the mediastinum (the space between the lungs), in which case they are referred to as primary mediastinal B-cell lymphomas. But they are also sometimes found in other areas such as lymphoid tissue in the neck or abdomen, or in the bones.
Treatment is basically the same for both types of large cell lymphoma, although the cure rate tends to be slightly higher for the diffuse large B-cell type.
Last Revised: 01/27/2016