A lipoma is a lump under the skin that occurs due to an overgrowth of fat cells. Doctors consider lipomas to be benign tumors, which means that they are non-cancerous growths.
However, people may wish to remove a lipoma that causes pain, complications, or other symptoms. Some people also have concerns about the cosmetic appearance of lipomas.
Lipomas can occur anywhere on the body where fat cells are present, but they tend to appear on the shoulders, chest, trunk, neck, thighs, and armpits. In less common cases, they may also form in internal organs, bones, or muscles.
Lipomas feel soft and may move slightly under the skin when people press down on them. They usually grow slowly over a period of months or years and typically reach a size of around 2–3 centimeters (cm). Occasionally, people have giant lipomas, which can grow to more than 10 cm.
In this article, we look at the causes, symptoms, and health implications of a lipoma. We also cover risk factors, diagnosis, and removal.
Doctors do not fully understand what causes a lipoma.
Some people inherit a faulty gene from their parents that can cause one or more lipomas. This is rare and is known as familial multiple lipomatosis.
Lipomas can occur more frequently in people with specific medical conditions, such as:
- Gardner’s syndrome
- Cowden syndrome
- Madelung’s disease
- adiposis dolorosa
Researchers have also suggested that some lipomas may result from an injury that involves a substantial impact on the area.
A person with a lipoma will typically feel a soft, oval-shaped lump just beneath the skin. Lipomas are usually painless unless they affect joints, organs, nerves, or blood vessels. In most cases, they do not cause other symptoms.
A person with a lipoma that occurs deeper under the skin may not be able to see or feel it. However, a deep lipoma may place pressure on internal organs or nerves and cause associated symptoms. For example, a person with a lipoma on or near the bowels may experience nausea, vomiting, and constipation.
Lipomas are benign masses of fat cells. However, experts disagree about whether or not lipomas have the potential to become cancerous. A cancerous mass of fat cells is known as a liposarcoma.
Based on research, many experts have concluded that liposarcomas do not develop from lipomas but are, in fact, a different type of tumor. They believe that doctors sometimes mistake liposarcomas for lipomas.
Conversely, other experts think that lipomas may contain both cancerous and pre-cancerous cells, but that it is extremely rare for a lipoma to become cancerous.
It is fairly common for a person to develop a lipoma. Experts estimate that around 1 percent of people have a lipoma.
People who have a family relative with one or more lipomas have a higher risk of developing this condition. Lipomas are also more likely to occur in people aged between 40 and 60 years old.
Other risk factors for developing a lipoma may include:
People should always tell their doctor if they notice changes in a lipoma or if more lumps appear. These changes might involve the lipoma:
- increasing in size or suddenly growing very quickly
- being painful
- becoming red or hot
- turning into a hard or immovable lump
- causing visible changes in the overlying skin
Doctors can usually diagnose a lipoma with a simple physical examination.
They may start by inspecting and feeling the lump. If the lipoma is large or painful, the doctor may order tests to check if it is cancerous.
They may use the following tests:
Lipomas are usually harmless, so most people do not need to have surgery to remove them. People may want to remove a lipoma that:
- is cancerous
- is large or growing quickly
- causes bothersome symptoms, such as pain and discomfort
- interferes with normal body functions
- causes distress for cosmetic reasons
- the doctor is unable to confirm is a lipoma rather than another type of tumor
A doctor can often remove a lipoma surgically. One method is to make a small cut in the skin and then squeeze out the lipoma. The person is usually under local anesthesia during the procedure and should be able to return home on the same day.
A doctor may need to make a more significant incision to remove larger lipomas entirely. It is also possible to remove some lipomas using liposuction. To do this, the doctor will need to cut into the lump and insert a thin, hollow tube through the incision. They will then use the tube to suck the mass of fat cells out of the body.
After surgery, the doctor will usually send the lipoma material to a laboratory for analysis. These types of operations will often only leave a small scar once the wound has healed.
Lipomas are harmless, fatty tumors that can form under the skin. They are usually painless and do not require treatment. However, a doctor can surgically remove a lipoma if it is causing pain or other symptoms, or if the person wants to get rid of it for cosmetic reasons.
Fatty tumors can be benign or cancerous. However, experts are unable to agree whether or not lipomas themselves can become cancerous. It is essential to seek medical advice if a lipoma becomes painful, gets larger, or changes in any other way.