I copied this from CancerLink:"Lymphedema is the buildup of lymph in the tissues, mainly in the fat just under the skin, and is caused by a problem in the lymphatic system. Lymphedema is an abnormal collection of excess tissue proteins, fluid (edema), chronic inflammation, and thickening and scarring of connective tissue. Lymphedema is a common side effect of cancer and cancer treatment. Lymphedema may cause long-term physical, psychological, and social problems for some patients. The lymphatic system is made up of vessels that are similar to blood vessels, but it carries lymph instead of blood. Unlike the blood system, which circulates through every part of the body, the lymphatic system drains lymph away from each part of the body. The lymphatic system collects fluid and protein from body tissues and returns it to the bloodstream. Proteins and substances too big to fit into veins are moved through the lymphatic system. Edema may occur when these substances are in excess and the lymphatic system becomes overwhelmed or blocked. Lymphedema may be either primary or secondary. Primary lymphedema is a rare inherited condition in which lymph nodes and lymph vessels are absent or abnormal. Secondary lymphedema is usually caused when the lymphatic system is blocked or cut and may be caused by infection, cancer, or scar tissue. The most frequently affected lymph nodes are in the pelvis, legs, and under the arms." If you would like to e-mail me I can direct you to many excellent sites regarding lymphedema.