The spleen is the organ that is responsible for purifying the blood as well as storing blood cells. It is positioned in the superior abdomen, and is the largest lymphatic organ in the body. The spleen serves a valuable role in immune function because it purifies the blood and helps the immune system with recognize and attack foreign antibodies and disease. The spleen is composed of the red and white pulp. The white pulp produces and grows immune cell as well as blood cells. On the other hand, the red pulp is responsible for purifying the blood and removing dead or old blood cells. The condition known as splenomegaly exists when the spleen becomes enlarged due to disease. When this occurs the spleen can rupture and cause additional damage. The surgical procedure splenectomy, is often needed to remove the enlarged spleen. When the spleen is removed the liver will assume the portion of the spleen's responsibility for fighting germs and coordinating the immune system. Splenomegaly has been associated with the following diseases: thrombocytopenia mononucleosis sickle cell disease cancer