A lipoma is a benign tumor composed of adipose (fat) tissue. The most common type of lipoma is the subcutaneous lipoma which appears as a lump just under the skin, but lipomas can occur in almost every organ. However, they are almost always harmless and require no treatment unless they become cosmetically concerning.
The exact mechanism behind lipoma formation is unknown, though people who have close relative with lipomas are more likely to develop lipomas themselves, and a link between previous trauma and lipoma formation has been suggested but no solid evidence for this theory has been found. Multiple lipomas can rarely be a symptom of an underlying disease – lipomatosis is a rare genetic condition that results in the formation of multiple lipomas, dercum disease is a rare condition involving multiple painful lipomas, and benign symmetric lipomatosis is a rare condition that most commonly affects middle ages men with a long history of alcoholism that results in excess fat deposits and lipomas in the head/neck/shoulder region.
Most lipomas require no treatment, but if removal is desired they can be easily treated through surgical excision or liposuction. Surgical excision has the highest cure rate and lipomas rarely reoccur following treatment. Liposuction results in less scarring but has a higher rate of reoccurrence – especially if the fibrous capsule that surrounds the tumor is left intact. Therefore, liposuction is typically reserved for small lipomas or those in cosmetically sensitive areas such as the face.