Overview

A lipoma is a common, non-cancerous growth made up of fat cells. Think of it as a small, contained pocket of fatty tissue that has gathered just beneath the surface of your skin. These growths are very common and are considered benign, which means they are not a form of cancer and will not spread to other parts of your body.

Most people who develop these lumps are between the ages of 40 and 60, though they can appear at any age. They are found in about 1 in every 1,000 people. While they most often appear in the layer of fat just under the skin on the shoulders, neck, back, arms, buttocks, or thighs, they can technically develop anywhere on the body, including the forehead or even in deeper areas like the oral cavity. They are usually solitary, meaning you only have one, but some people may develop multiple lipomas, a condition sometimes referred to as lipomatosis.

Symptoms and Causes

Because lipomas grow very slowly, you might not notice one until it has reached a certain size. They are generally harmless, but it is always sensible to have any new or changing lump checked by a healthcare professional to be certain of what it is.

Symptoms

When you touch a lipoma, it typically feels like a soft, squishy, or "doughy" lump. Because it sits just under the skin, it is usually easy to move slightly when you press on it with your fingers. The skin over the top of the lump usually looks and feels completely normal.

Key characteristics include:

• Size: They can range from the size of a small pea to over 10 centimetres across.
• Texture: They feel soft and rubbery.
• Movement: They are typically freely mobile, meaning they shift slightly when you push them.
• Pain: Most lipomas are painless. However, if a lipoma grows large enough to press against a nearby nerve, or if it contains many small blood vessels, it may cause some discomfort or pain.
• Growth: They grow very slowly over many years.

Causes

The exact reason why these fat cells decide to group together into a lump is not fully understood. However, experts believe a few factors may play a role:

• Genetics: There is often a family history of lipomas, suggesting that your genes may make you more likely to develop them.
• Age: They are most common in middle age, suggesting that changes in how our bodies store fat over time might be a factor.
• Injury: Some people notice a lipoma appearing after a minor injury to a specific area, though it is not clear if the injury directly caused the growth.
• Other factors: In rare cases, hormone imbalances or specific health conditions, such as Dercum’s disease, may be linked to the development of multiple lipomas.

Diagnosis and Investigations

If you find a new lump, it is important to visit your GP. While the vast majority of these lumps are harmless, a doctor will want to examine it to rule out other, more serious conditions.

Diagnosis

In most cases, a doctor can diagnose a lipoma simply by feeling it. They will check how soft it is, whether it moves under the skin, and if it has changed in size recently. They will also look at the skin over the lump to ensure there are no unusual changes, such as redness, bleeding, or broken skin.

Investigations

If your doctor is unsure about the diagnosis, or if the lump has some features that need further investigation, they may refer you for imaging tests. These tests help the doctor see exactly what the lump is made of and how deep it sits.

• Ultrasound: This uses sound waves to create an image of the lump. It is very good at confirming that the growth is made of fat.
• MRI or CT scans: These provide more detailed pictures of the area. They are used if the lump is in a deeper location or if the doctor needs to see exactly how it sits in relation to nearby muscles or nerves.
• Biopsy: In rare cases, a doctor might use a fine needle to take a tiny sample of the tissue to be looked at under a microscope in a laboratory. This is done to confirm the diagnosis and rule out other types of growths.

Management and Treatment

Because lipomas are benign and usually painless, they often do not require any treatment at all. Many people choose to simply monitor them over time. However, your doctor may discuss treatment options if the lipoma is causing you pain, if it is growing rapidly, or if it is affecting your daily activities or appearance.

Common approaches include:

• Observation: If the lump is small and not bothering you, the best approach is often to leave it alone and keep an eye on it.
• Surgical Excision: This is the most common way to remove a lipoma. It involves a minor procedure where the lump is "shelled out" from under the skin.
• Liposuction: This involves using a thin tube to suck the fatty tissue out through a small incision.
• Steroid Injections: Sometimes, injections can be used to help shrink the size of the lipoma, though this does not usually remove it entirely.

Please note that on the NHS, removal is generally only offered if the lump is causing symptoms or growing significantly. Removal for purely cosmetic reasons is not typically funded by the NHS.

Prevention

Currently, there is no known way to prevent a lipoma from forming. Because the exact cause is often linked to genetics or natural changes in the body as we age, you cannot "catch" them or cause them through your lifestyle. Maintaining a healthy weight and general good health is always beneficial, but it does not guarantee that you will not develop a lipoma.

Outlook / Prognosis

The outlook for someone with a lipoma is excellent. These are harmless, non-cancerous growths that do not turn into cancer. Once a lipoma is removed, it is very unlikely to return in the same spot. Most people live their entire lives with one or more lipomas without any issues at all.

While they are benign, you should always keep an eye on your lump. You should contact your GP if you notice any of the following "red flag" changes:

• The lump starts to grow quickly.
• It becomes hard or firm to the touch.
• It becomes fixed in place and no longer moves when you push it.
• It becomes painful or tender.
• You notice changes to the skin over the lump, such as redness, ulceration (an open sore), or bleeding.

If you notice these changes, it does not necessarily mean something is wrong, but it is important to have a professional check it to ensure everything is as it should be. For the vast majority of patients, a lipoma is simply a minor, manageable part of life that requires no special long-term care.