Lipomas are soft deposits of body fat that grow under the skin, causing round or oval lumps.
A lipoma appears as a smooth, soft bump under the skin. Lipomas range in firmness, some feeling rather hard. The skin over the lipoma has a normal appearance. Lipomas rarely grow more than 3 inches (about 7.5 centimeters) across. They can develop anywhere on the body but are particularly common on the forearms, torso, and back of the neck. Lipomas are more common in women than in men. Some people have only one, but other people develop many lipomas. Lipomas rarely cause problems, although they may occasionally be painful.
Usually, a doctor can easily recognize lipomas, and no tests are required for diagnosis. Lipomas are not a form of cancer, and they rarely become cancerous. If a lipoma begins to change in any way, a doctor may do a biopsy (removal of a tissue sample for examination under a microscope). Treatment usually is not required, but bothersome lipomas may be removed by surgery or by liposuction (removal of fat with a suction device).
Last full review/revision September 2008 by Daniel W. Collison, MD