Leukemia vs. Lymphoma: What’s the Difference?

Prevalence and age

Leukemia is the most common type of childhood cancer. Lymphoma is also one of the more frequently seen types, but it’s less prevalent. According to the American Cancer Society, leukemia accounts for about one-third of cancer cases in children and teens, while lymphoma accounts for about 12%.

There's also a difference in when the two types of cancer are most likely to develop. Childhood leukemia is usually diagnosed in kids between 2 and 6 years old. Childhood lymphoma is more common in the teen years.

Origin

Leukemia develops in tissues where blood cells are made, typically in bone marrow (the spongy substance at the center of bones). In leukemia, the bone marrow makes lots of abnormal blood cells (usually white blood cells) that crowd out healthy blood cells.

Lymphoma begins in the lymphatic system. A key part of immune function, the lymphatic system includes the bone marrow, spleen and tonsils as well as lymph nodes, ducts and vessels. Lymphomas develop when lymphocytes (a type of white blood cell) become cancerous.

Types

There are many types of leukemias and lymphomas. Leukemias are categorized by how fast the disease grows and by the kind of cell that becomes cancerous.

Acute leukemias progress quickly if they're not treated. Chronic leukemias, on the other hand, grow slowly. Leukemias may begin in lymphocytes or in myeloid cells, which can develop into white blood cells, red blood cells or platelets. By far the most common type of leukemia seen in children is acute lymphocytic leukemia, or ALL.

Lymphomas are divided into two main categories: Hodgkins Lymphoma and non-Hodgkin's lymphoma. The two are differentiated by examining the cancer cells under a microscope. If a specific type of cell, called a Reed-Sternberg cell, is present, the disease is considered Hodgkin's lymphoma; if Reed-Sternberg cells aren't seen, it's non-Hodgkin's lymphoma.

There are many types of both non-Hodgkin's and Hodgkin's lymphomas.

Causes and risk factors

Scientists don't know what causes lymphoma or leukemia, but each disease has certain factors that seem to increase a person's risk.

Risk factors for childhood leukemia include:

• Genetic conditions. Children with certain genetic conditions, such as Down syndrome and neurofibromatosis type 1, are at higher risk.
• Family history. Children appear to be more likely to develop leukemia if a sibling had it.
• Previous cancer treatment. Past exposure to chemotherapy or radiation therapy may increase someone's risk.

Risk factors for lymphoma include:

• Infections. Being infected by the Epstein-Barr virus may increase a child's likelihood of developing Hodgkin's lymphoma.
• Immune issues. Having a weakened immune system can increase the risk of lymphoma.

Symptoms

Some symptoms – such as unexplained fatigue, fever and weight loss – may be seen in both leukemia and lymphoma. But there are some differences. For example, bruising or bleeding easily and developing petechiae (small red spots on the skin caused by bleeding) can be signs of leukemia.

Many cancer symptoms can also be caused by other conditions. If your child has these symptoms or you have any reason to be concerned about leukemia or lymphoma, please bring your child to a doctor for a thorough evaluation.