What Is A Lipoma? 

A lipoma is a supple, doughy lump of fat cells beneath the skin. These fatty spots are benign, as the fat cells in the lump are encapsulated and cannot invade the surrounding tissue – which means that they are non-cancerous. 

Nevertheless, patients must have an unusual lump officially diagnosed as a lipoma by a healthcare professional before they can eliminate the risk of cancer. This is particularly important with lipomas, as they often resemble liposarcoma – a rare cancer that we discuss in greater detail below. 

Types of Lipoma

A lipoma is a lump that consists of fatty tissue, and so – as there are different types of fatty tissue in the body – there are also different types of lipoma. 

The most common type of lipoma is known as conventional lipoma. These lipomas are made up of white fat cells. White fat is the predominant type of fat in the body: it is stored around the waist, hips and thighs, and is responsible for storing energy. Lipomas are small balls of white fat growing under the skin, which looks and feels like soft, malleable skin spots.

Whilst the white fat cells inside conventional lipomas are all the same size, there are some lipomas which consist of fat cells that are different sizes. These are called pleomorphic lipomas.

Although they are less common, lipomas can also be made up of brown fat cells (the type of fat that is responsible for regulating body temperature). These are known as hibernomas. 

Fibrolipomas consist of fibrous and fatty tissue, whilst spindle cell lipomas are made up of long, spiked fat cells which – as their name suggests – resemble spindles.

Myelolipomas differ from other types of lipoma in that they produce white blood cells. Meanwhile, angiolipomas are unusual because they have blood vessels running through them. It is for this reason that angiolipomas can be quite painful – unlike other forms of lipomas, which are usually painless. 

Who Gets Lipomas? 

Anyone can get a lipoma. In fact, they are very common, with 1 in 1,000 people developing one at some point in their lifetime. 

Nevertheless, some people are at greater risk of having a lipoma than others. People between the ages of 40 and 60 are most susceptible, and they are slightly more common in women than men. They also run in families, and so you are more likely to develop a lipoma if you have relatives who have them. 

What Is Liposarcoma?

Liposarcoma is a rare type of cancer that grows in the body’s fat cells. It can occur at any site where fat cells are stored in the body, but it usually develops in the arms, legs, back of the abdomen, and the groyne. 

The first symptom of liposarcoma is typically a soft lump growing in an area of fatty tissue. Sometimes, this is the only symptom that ever appears, but the cancer can also cause tiredness, feverishness, chills and night sweats, as well as weight gain or loss. 

Liposarcoma is a potentially life-threatening condition, so if you find an unusual growth or lump on your skin, you must have it assessed by a medical professional immediately. 

Types of Liposarcoma

There are five different subtypes of liposarcoma, and these are:

1. Well-differentiated Liposarcoma. This is the most common form of cancer, which grows very slowly. It is unusual for this type of condition to spread to other parts of the body, though it is common for it to regrow after initial treatment. 
2. Myxoid Liposarcoma is the second most common subtype. It is usually found in the arms and legs, though it can spread to distant parts of the body, including the muscles and bones. 
3. Pleomorphic Liposarcoma is the rarest subtype, accounting for fewer than 5% of all liposarcomas. However, it is the most likely form of cancer to spread to other parts of the body or regrow after treatment. 
4. Dedifferentiated Liposarcoma is a more aggressive form of well-differentiated liposarcoma. In fact, dedifferentiated tumours begin as well-differentiated tumours, but then a change in the DNA of the cancer cells occurs, which causes these cells to grow and spread more rapidly. These tumours often appear in or around the abdomen. 
5. Round Cell Liposarcoma is a more aggressive form of Myxoid Liposarcoma. A patient develops this subtype of cancer when the cells inside a myxoid liposarcoma tumour combine with round cells, forming a new tumour, called a round cell tumour. This tumour is more likely to invade healthy tissues and spread to different parts of the body, including muscles, bones and organs – such as the heart or lungs. As myxoid tumours tend to appear in the arms and legs, round cell tissues are most commonly found in the limbs, too. 

Who Gets Liposarcoma? 

Anyone can develop liposarcoma. However, people between the ages of 50 and 60 are most likely to develop the condition, and men are at greater risk than women. It is very rare for children to develop liposarcoma.  

Liposarcoma occurs when fat cells in the body mutate, which causes them to multiply rapidly – leading to the growth of a tumour. Consequently, genes play a factor in the development of cancer, and so patients with a family history of liposarcoma are at greater risk. 

Finally, patients who have undergone radiation treatment in the past, or who have experienced long-term exposure to toxic chemicals, are more likely to develop liposarcoma. 

What are the Differences between a Lipoma and Liposarcoma?

Lipomas and liposarcoma have a lot in common, so it’s easy to confuse the two. However, there are some key differences to look out for, which we list below. 

However, as you read this list of differences, please bear in mind that the only definitive way to know whether you have liposarcoma or a lipoma is to be examined by a medical professional. Liposarcoma is a potentially fatal condition, and so you must see a doctor if you think that you might suffer from it. 

Differences in Characteristics and Symptoms

A lipoma is an unusual growth on the skin, which consists of fatty tissue. It is soft and malleable to the touch: it will move under gentle pressure from the finger. They are the same colour as your skin, and they vary in size: they can be less than 1cm in diameter, or 5cm wide. Nevertheless, they all grow over time, and they do not disappear on their own. 

Liposarcoma also forms in fatty tissue and causes the growth of soft lumps, which is where confusion can arise. However, a key difference is that lipomas grow just beneath the surface of the skin (typically around the arms, torso, shoulders and neck – though they can appear anywhere on the body). 

Liposarcoma, meanwhile, causes a tumour to grow much deeper in the body, usually in the arms, legs or abdomen. If the growth appears to be close to the surface of the skin, therefore, then it is probably a harmless lipoma. 

Additionally, lipomas are ‘encapsulated’ – which means that they cannot invade the surrounding tissue and spread to other areas of the body. By contrast, liposarcoma tumours can invade other tissues, including organs, muscles and bones. 

It is also unusual for a lipoma to cause pain. The only exception here is if the lipoma is an angiolipoma (a lipoma with blood vessels running through it), as these can be quite sensitive and sore. Moreover, a lipoma can be painful if it begins to press on a nearby nerve as it grows.

Besides this, however, a lipoma will not cause any other symptoms: it is simply a soft lump on the skin. Liposarcoma, however, is often accompanied by lots of different symptoms, such as tiredness, weight gain or loss, a fever, night sweats or chills. It is common to experience feelings of numbness, tingling ache, pain or swelling in and around the area where the tumour is growing, too. 

The symptoms caused by liposarcoma also depend on the site at which the tumour grows. For example, when a liposarcoma tumour grows in the arms or legs, it can cause feelings of tenderness, weakness, swelling and pain. When the tumour develops in the abdomen, patients may experience constipation, trouble bleeding, blood in the stool or vomit, or feelings of fullness after small amounts of food. 

In some cases, liposarcoma can cause no symptoms at all, so it is important to have a lump on the skin assessed by a doctor, even if you are not experiencing any other features of the condition. 

Differences in Origin and Growth

Lipomas and liposarcoma tumours originate in different parts of the body. Lipomas grow just under the surface of the skin. Although experts are not sure exactly why these harmless fatty lumps appear, the cause is suspected to be genetic, since they tend to run in families. 

There is also some evidence to suggest that an injury can trigger the growth of a lipoma. Additionally, they can be a symptom of an underlying health condition: Madelung’s disease is a disorder which can cause lipoma cysts to grow around the neck and shoulders, whilst Dercum’s disease is a rare condition which can cause painful lipomas to form around the arms, legs and abdomen. 

By contrast, a liposarcoma tumour grows much deeper in the fat cells of the body. As with all cancers, this happens when the cells genetically mutate, and the mutation then instructs the cells to multiply uncontrollably at a rapid pace, leading to the formation of an abnormal mass of cells – or tumour – in the body. 

Experts are not agreed on exactly what causes fat cells in the body to mutate in this way. However, the condition can be inherited, as it often runs in families. Moreover, patients who have had radiation therapy before, or experienced long-term exposure to workplace chemicals (such as vinyl chloride), are more likely to suffer from liposarcoma, so these are possible causes for the mutation. 

Different Risk Factors

Anyone – of any age or sex – can develop both benign lipomas and malignant liposarcoma. However, different groups of people are at greater risk in each case. 

People between the ages of 40 and 60 are most likely to have a lipoma, and women are at greater risk than men. Conversely, people between the ages of 50 and 60 are most likely to suffer from liposarcoma, and men are at greater risk than women.

As we mentioned above, patients who have a family history of cancer, have previously undergone radiation therapy, or have been frequently exposed to toxic chemicals, are also at an increased risk of liposarcoma. Meanwhile, patients who have experienced an injury or who suffer from an underlying health condition such as Madelung’s disease, Dercum’s disease or Gardner syndrome are at an increased risk of developing a non-threatening lipoma. 

Differences in Diagnosis

Whether the lump on your body is a lipoma or a symptom of liposarcoma – or something else entirely – it needs to be examined by a medical professional in order to be diagnosed properly.

It is possible to diagnose a lipoma through a physical examination. However, in some cases, further tests will have to be performed, such as a biopsy – which is when a small tissue sample is extracted from the lump and sent away to be studied beneath a microscope. 

Liposarcoma cannot be diagnosed through a physical examination alone, and a biopsy will certainly have to be performed. Additionally, it is likely that further tests will have to be administered, such as a computed tomography (CT) scan, as this locates the tumour and determines its size. Similarly, magnetic resonance imaging (an MRI scan) may be required to see whether the muscles, nerves and blood vessels surrounding the tumour have been affected by the condition, too. 

Sometimes, these tests are also carried out on lipomas (as well as other imaging tests, such as an ultrasound) to ensure that the lump is a lipoma and not a cyst, or to check whether the lipoma is pressing on any nearby nerves. 

Differences in Treatment

Once a lump is diagnosed, it can be treated appropriately. 

One key difference here is that lipomas are non-cancerous and completely harmless, so it’s not necessary to have them removed at all. Liposarcoma, however, is a potentially life-threatening cancer, so patients will need to begin treatment immediately.

Nevertheless, many patients choose to have lipomas removed for cosmetic reasons since they never disappear on their own. Similarly, if a lipoma is painful (because it has a lot of blood vessels running through it, or it is pressing on a nearby nerve) then it may become necessary to have it removed. 

A lipoma is removed via surgery. Normally, a local anaesthetic is used to reduce discomfort during the procedure. However, a general anaesthetic may be required if the lipoma is very large or deep.

Your surgeon will mark out the areas where incisions need to be made using a pen, and then the lipoma will be cut out of the skin using a scalpel. This will create a hole, which will be stitched closed. The skin will have completely healed after approximately 10 to 14 days have passed since the surgery, and the stitches will be removed at this time. 

Liposarcoma can also be treated via surgery, provided that it is possible for the tumour to be surgically removed. If this is not possible, then your doctor will recommend an alternative treatment, such as radiation therapy. This procedure uses powerful beams of energy (such as X-rays) to kill the cancerous cells that make up the tumour. 

Radiation therapy may also be used in combination with surgery: for example, it may be performed prior to a surgical procedure to shrink the tumour so that it can then be surgically excised. Alternatively, radiation therapy may be used after surgery in order to eliminate any remaining cancer cells. 

Finally, liposarcoma can also be treated via chemotherapy, which uses drugs to kill cancer cells. However, only certain types of liposarcoma are responsive to chemotherapy, so it is not a suitable treatment for everyone. 

MORE ABOUT LIPOMA REMOVAL TREATMENT

FAQs

How do I know if I have liposarcoma or a lipoma?

The only way to know for sure whether you have a lipoma or you suffer from liposarcoma is to have the lump on your skin assessed by a healthcare professional. 

Are liposarcoma tumours hard or soft?

Liposarcoma tumours are made up of cancerous fat cells, so they are soft and rubbery to the dartouch. In fact, they can move under gentle pressure from your finger. 

Can a lipoma turn into liposarcoma?

No, lipomas are non-cancerous and cannot develop into liposarcoma. Nevertheless, you should always arrange a check-up with your doctor if you notice that your lipoma has changed in some way, or if a second lump appears. 

How big is a liposarcoma tumour?

A liposarcoma can be any size. They tend to grow very slowly but can become very big with time. 

Does liposarcoma go away?

Liposarcoma does not go away on its own, and patients will require urgent treatment to tackle the condition. Nevertheless, when liposarcoma is diagnosed and treated early, the tumour can be removed and the cancer is essentially cured. However, it is possible for the tumour to grow back, so patients may require regular check-ups with a doctor for years after the treatment. 

References:

• https://www.ncbi.nlm.nih.gov/books/NBK507906/
• https://orthoinfo.aaos.org/en/diseases–conditions/lipoma
• https://www.mskcc.org/cancer-care/types/soft-tissue-sarcoma/types/liposarcoma

About the Author

Dr Suhail Alam

Dr Alam is devoted to providing high quality, holistic, patient centred care designed to make patients look and feel their best. He has a specialist interest in Hair Restoration Surgery and Regenerative Medicine.

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