Lipoma: what it is, causes, symptoms and whether it needs removing

The BAD says the exact cause of lipomas is not well understood, and most arise spontaneously without a clear cause. It lists some risk factors that may increase the likelihood of developing them: age, gender, hormone imbalances and trauma to the skin area.

The BAD adds that some research suggests that if a family member has had lipomas, you may be at higher risk too. Dercum disease is an example of a condition in which people develop lipomas and genetics may be involved.

A lipoma is a non-cancerous (benign) lump made up of fat cells, according to the BAD. They are usually located in the fatty layer under the skin, and rarely in deeper muscles and organs. They can occur almost anywhere on the body but are most commonly found on the shoulders, arms, back, buttock and thigh.

People can develop more than one lipoma. The BAD says they can affect people of all ages but tend to appear during middle age. The NHS says lipomas are common.

The NHS says lipomas feel soft and squishy, can be anything from the size of a pea to a few centimetres across, may move slightly under your skin if you press them, are not usually painful, grow slowly and can appear anywhere on your body.

The BAD describes a small, painless, rubbery-textured lump beneath the skin that moves easily with slight finger pressure. Most are painless, but some may be painful if they press on nerves and other structures or if they contain many blood vessels. They may go unnoticed for years until they have grown in size, and some people find them uncomfortable or dislike how they look.

The NHS says a GP will usually be able to tell if the lump is a lipoma and, if there is any doubt, may refer you for a scan to check it. The BAD says diagnosis is made by examination by a healthcare professional, and that sometimes an ultrasound, CT or MRI scan is needed to tell a lipoma from other benign skin lesions such as cysts, or from cancer tumours.

If the lump is increasing in size, the BAD says further investigations such as a biopsy or full excision might be organised to rule out the very rare possibility that it is a cancer such as liposarcoma.

The NHS says lipomas are harmless and do not usually need to be removed, and would only be removed on the NHS if the lipoma was growing or causing symptoms because of where it is. If you have it removed, it may be sent to a laboratory to check it is a lipoma. The BAD agrees there is no medical need to remove the vast majority, that they are often removed for cosmetic reasons, and that these procedures are not routinely offered on the NHS.

The national Evidence-Based Interventions policy on removal of benign skin lesions, adopted by NHS commissioners, says treatment carries a small risk of infection, bleeding or scarring and is not usually offered by the NHS if it is just to improve appearance. For lipomas it lists lipomas on the body larger than 5 cm, or in a deeper position (described as sub-facial), with rapid growth or pain, which should be referred to a sarcoma clinic. More general criteria include regular bleeding, repeated infection, pain requiring long-term daily medication, obstruction or significant impact on function.

The NHS says you can pay to have a lipoma removed at a private clinic, but it may be expensive, and a GP can advise where to get treatment.

It can be hard to tell by looking. The BAD says scans are sometimes needed to distinguish a lipoma from other benign lesions such as cysts, and the NHS says a GP will usually be able to tell. The EBI policy notes that epidermoid and pilar cysts are sometimes incorrectly called sebaceous cysts.

In general, the NHS describes lipomas as soft and squishy and slightly movable under the skin. A lump that is hot, red and painful, or hard and fixed, should be seen by a GP.

The NHS says to see a GP if you get a lump anywhere on your body, a lump is painful, red or hot to touch, a lump is hard and does not move, or a lump increases in size. The BAD says that if you notice a new or growing lump in your skin you should consult a healthcare professional, and to seek advice if there is fast growth, it cannot be moved with finger pressure, bleeding, ulceration, significant pain or pain that is not solely pressure related.

On the NHS, a GP assesses the lump and arranges a scan or referral if there is doubt, and removal is considered where the lipoma is growing or causing symptoms. The EBI policy says the decision about whether a patient meets criteria is primarily with the referring clinician and that referral does not guarantee treatment.

Private removal is available, with the NHS noting it may be expensive. Whichever route you choose, ask whether the removed tissue will be sent for laboratory testing, as the NHS describes, and what scarring to expect.