A lipoma is an overgrowth of fat cells that form a noncancerous lump under the skin, as reported by Cancer Research UK. The cause of lipoma is not clear, but the tendency to develop them is hereditary.
Lipomas rarely develop into a cancerous sarcoma, and it is possible to have multiple lumps at the same time. A lipoma usually does not cause pain unless it presses on other organ or nerves and causes symptoms. Surgical removal of lipomas is advised if it becomes painful or tender, infected or inflamed, has foul-smelling discharge, increases in size, and interferes with movement or function, according to WebMD.