Lipomas: Causes, Symptoms and Treatments
Lipomas are harmless fatty lumps that grow under the skin. We speak to a specialist to find out about causes, symptoms and how they can be treated
What is a lipoma?
A lipoma is a lump under the skin caused by an overgrowth of normal fat cells in the body. These cells are called adipocytes. The lump is classed as a benign (non-cancerous) tumour.
These lumps vary in their firmness, so some feel soft and others hard.
A lipoma can grow slowly over a few months. You may even have one that you've noticed there for a long time. Some people have multiple lipomas in different locations.
Where on the body do lipomas grow?
Lipomas can occur anywhere on the body. The most common locations are the arms, legs, shoulders, and the back of the neck just beneath the skin.
Sometimes they can also present deep within the muscle, in which case they may not present as a distinct lump.
Why do lipomas form?
We don't know definitively why such lumps develop and why they can grow in size.
One theory is that they are caused by localised trauma (for example a knock or bump), though some think they are there already and that the trauma simply makes them feel harder and more apparent than normal.
There are also thought to be genetic factors at play, as they run in families, and certain genetic conditions make you more likely to develop a lipoma.
You are more likely to develop a lipoma if you are middle aged (between 40 and 60), but they can happen in anyone of any age, and can even be present from birth.
Lipomas rarely cause pain and are usually asymptomatic. For many people they are simply an annoyance.
What are the symptoms?
Lipomas rarely cause pain and are usually asymptomatic. For many people they are simply an annoyance, either aesthetically or because they can potentially rub on clothing and cause irritation.
Sometimes, if a lipoma is larger than about 5cm in diameter in size, the lump can press on nearby structures such as muscles or nerves. This can cause symptoms which might be disruptive, or occasionally a cause for concern.
For example, you might experience pins and needles or, with very large and deep growths, you might experience swelling, pain or reduced function.
When should I see a doctor about the lump?
It's always best to get a lump checked out, even if you think it's nothing to worry about. It's better to have peace of mind and early diagnosis than to run the risk, however small, of waiting until it's too late.
You should always see a doctor if any lump develops, anywhere on your body. This is particularly true if the lump is painful, red or hot, or if it's hard and doesn't move.
You should also see your doctor if an existing lump gets bigger or develops any of the above symptoms, especially if it is deep under the superficial skin structures.
Could my lipoma be cancerous?
Lipomas are not cancerous. They are classed as benign lumps.
People often ask me, are lipomas dangerous? Normally the answer is no.
Very occasionally, lipomas can increase in size over time and form atypical lipomatous tumours, which do have a small chance of developing into a cancer called soft tissue sarcoma.
How do you diagnose a lipoma? What tests will I need?
If you think you have a lipoma, speak to your GP or visit a specialist to get a diagnosis. A GP can sometimes diagnose your lump, but if they're in doubt they'll refer you to a specialist for a scan.
Normally you will have an ultrasound from a specialist radiologist who will assess your lump.
Some will need further assessment to diagnose a lipoma, particularly large ones. Some people will need an MRI scan and very occasionally you might need a biopsy if you have, or we think you have, something called a complex lipomatous lesion.
If you want your lump removed for any reason, you will need to have it removed surgically. Lipomas don't really disappear by themselves.
Will I always have this lump or can it be removed?
For many people, it is safe to leave a lipoma because it's not dangerous or causing any symptoms.
If you want your lump removed for any reason, you will need to have it removed surgically. Lipomas don't really disappear by themselves.
What should I expect from surgery and what are the risks?
Lipomas are best removed by surgery under anaesthetic. We normally use local anaesthetic, meaning you only need to come in as a day case patient (you don't need to stay overnight).
The risks of this surgery are very low but in rare cases you can experience scar irritation or infection.
Your consultant will talk you through all the risks, however small, as well as exactly what to expect from the procedure.
Will the lipoma come back?
It is incredibly rare for the growth to come back, so, once you've had the procedure you can stop worrying about it!
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How do I book an appointment?
If you're concerned about symptoms you're experiencing or require further information on this subject, talk to a GP or see an expert consultant at your local Circle Hospital.