Lipomas caused by fat cell overgrowth

Dear Doctors: I'm concerned about a large lipoma that is growing on the right side of my head. I know that lipomas are not supposed to be cancerous, but can it become so in the future? I'm considering having it removed. How is that done?

Dear Reader: A lipoma is a harmless rounded mass that forms due to an overgrowth of fat cells. Often shaped like a dome, lipomas usually don't cause pain or any other symptoms. Lipomas are typically found just below the surface of the skin, often on the trunk, neck, limbs or forehead. Less often, they may form within a muscle or inside an organ. When you touch a lipoma, the tissue feels rubbery and a bit springy. Because the mass isn't directly attached to the underlying muscle, it moves easily beneath the skin in response to pressure.

Discovering a lipoma can be alarming, particularly since they are technically tumors. However, they are benign, which means lipomas are not cancerous. It is estimated that 1% to 2% of people will develop a lipoma in their lifetime. The reason for this is not yet known. In some individuals, genetics appears to play a role. An inherited condition, known as familial multiple lipomatosis, can cause someone to develop numerous fatty growths on their body, some of them quite large. This condition arises due to a faulty gene that has been passed down, and it is not common.

Lipomas occur slightly more often in men than in women, and although they can appear at any age, they become more common in adults between the ages of 40 and 70. In addition to fat cells, some lipomas may contain blood vessels or other tissues.

While it's possible for a lipoma to become malignant, this is quite rare. When it occurs, the growth is known as a cancerous liposarcoma. For that reason, it's important to let your health care provider know about any changes to an