A system of lymph vessels, much like smaller veins, and lymph nodes make up your lymphatic system. This superhighway for your immune system collects waste, fluid, materials and other things from your body tissues and carries it through clear, watery lymph. It also collects viruses and bacteria.
Lymph cleans your body’s tissue cells, as the lymph fluid flows outward from capillary walls, carrying oxygen, white blood cells and essential nutrients to your cells. The lymph then carries away waste products, such as carbon dioxide.
Lymph vessels take the lymph fluid from all over your body to your chest, where it drains through a large vessel into a blood vessel near your heart.
Your lymph nodes filter harmful substances from your lymph fluid. These small structures like tiny, round peas also fight infection using immune cells that attack and destroy the germs carried through lymph vessels.
You have hundreds of lymph nodes in your body, each one working to filter fluid and debris from lymph vessels leading to those nodes. Lymph nodes at your elbow and under your arm filter lymph and provide immune cells for your fingers. Lymph nodes in the neck do the same for your head, scalp and face. You also have lymph nodes embedded deep in your body, under or between organs. Your lymph fluid flows throughout your body toward your chest, where fluid, salts and proteins flow into the bloodstream.
When you suffer infection, injury or cancer, your lymph nodes in that part of your body swell as they work hard to clean the bad cells out of your system. Anytime your lymph nodes swell you know something is wrong, but earaches, sore throat, fever or a cut infection cause lymph nodes to swell, too.
Your lymph nodes in your neck, groin and underarms swell most often. Only one area usually swells during an infection or illness. But other infections, some medicines, immune system diseases and cancers can cause swelling in more than one area of lymph nodes.
There are two ways cancer appears in your lymph nodes. It either begins in your nodes or spreads there from another part of your body. Cancer beginning in your lymph nodes is lymphoma. More commonly, cancer spreads to the lymph nodes from another part of your body.
Cancer in your lymph nodes starting from another part of your body travels to your nodes through your lymph. This is similar to how cancer cells travel through the blood to other organs. The cancer cells die or settle in a new region of your body. The ones settling in a new place grow and form new tumors. This is a cancer metastasis.
Cancer cells spreading to other parts of your body first break away from the original cancer tumor. They attach to a lymph vessel’s outside wall or a blood vessel’s outside wall. Then they move through your vessel’s wall and travel through the vessel to a new location. Cancer growing in your lymph nodes usually affects nodes nearest the original tumor.