The lymph system is a series of lymph nodes and vessels that move lymph fluid through the body. Lymph fluids contain infection-fighting white blood cells. Lymph nodes act as filters, capturing and destroying bacteria and viruses to prevent infection from spreading.

While the lymph system typically protects your body, lymph cells called lymphocytes can become cancerous. The names for cancers that occur in the lymph system are lymphomas. According to the Memorial Sloan Kettering Cancer Center (MSKCC), an estimated 75,000 Americans are diagnosed with lymphoma each year.