A lipoma is a growth of fat cells in a thin, fibrous capsule usually found just below the skin. Lipomas are found most often on the torso, neck, upper thighs, upper arms, and armpits, but they can occur almost anywhere in the body. One or more lipomas may be present at the same time. Lipomas are the most common noncancerous soft tissue growth. It's a benign tumor composed of adipose tissue.
Causes
The cause of lipomas is not completely understood, but the tendency to develop them is inherited. A minor injury may trigger the growth. Being overweight does not cause lipomas.
Symptoms
Lipomas usually:
Are small [0.4 in. (1 cm) to 1.2 in. (3 cm)] and felt just under the skin.
Are movable and have a soft, rubbery consistency.
Do not cause pain.
Remain the same size over years or grow very slowly.
Often the most bothersome symptom is the location or increased size that makes the lipoma noticeable by others.
Treatment
Usually, treatment of a lipoma is not necessary, unless the tumor becomes painful or restricts movement. They are usually removed for cosmetic reasons, if they grow very large, or for histopathology to check that they are not a more dangerous type of tumor such as a liposarcoma. This last point can be important as the actual identity of a "bump" is not known until after it is removed and professionally examined.
Lipomas are normally removed by simple excision. The removal can often be done under local anaesthetic, and take less than 30 minutes. This cures the majority of cases, with about 1-2% of lipomas recurring after excision. Liposuction is another option if the lipoma is soft and has a small connective tissue component. Liposuction typically results in less scarring; however, with large lipomas it may fail to remove the entire tumor, which can lead to re-growth.
There are new methods being developed that are supposed to remove the lipomas without scarring. One of them is removal by the use of injection of compounds that trigger lipolysis, such as steroids or phosphatidylcholine.
