What Is Lipoma

Lipomas are one of the most common types of benign tumours made up of adipose (fat) cells seen by clinicians. They are not known to be painful, and treatment is not usually required. 

Lipomas differ based on the fat tissue they are made up of and other features specific to the lump, such as blood vessels and surrounding cells. They grow beneath the skin in the layer of fat called adipose tissue but can grow into deeper layers. Lipomas are benign (non-cancerous) and grow at a slower rate. 

In this article, you will find information on the different types of lipoma, their causes, signs and symptoms, how they are diagnosed and the treatment that is available for them. 

Overview

Types of lipoma

Lipomas are primarily made up of fat cells called adipocytes. However, different subtypes exist based on how they appear under the microscope.

The most common type of lipoma is the conventional lipoma, which appears as mature white fat.¹ The atypical lipoma is associated with fat under deeper layers of the skin with a large number of cells.¹

Other types of lipoma include:

• Hibernoma (brown fat)
• Fibrolipoma (fat with fibrous tissue)
• Angiolipoma (fat with a large number of blood vessels)
• Myelolipoma (fat with tissue that makes blood cells)
• Spindle lipoma (fat attached to rod-looking tissue)
• Pleomorphic lipoma (fat cells of different shapes and sizes)

Causes of lipoma

The cause of a lipoma is largely unknown. However, genetics, certain conditions and age can increase the risk of developing lipomas.

Genetics:

Familial multiple lipomatosis - inherited faulty gene that causes the growth of multiple lipomas.²

Diseases:

Dercum’s disease is a rare condition that causes painful lipomas to grow on the arms, legs, and trunks.³

Gardner syndrome - a form of familial adenomatous polyposis (FAP). This is a condition which causes the growth of lipomas and varying health issues, including cancer.³

Madelung’s disease - also known as multiple symmetric lipomatosis. This causes lipomas to grow around the neck and shoulders. It is more common in men who drink excessive amounts of alcohol.³

Signs and symptoms of lipoma

As mentioned before, lipomas are common, and around 1 in 100 (1%) people will develop a lipoma.² Lipomas often grow in the upper back, shoulders, arms, buttocks and upper thighs.¹

You can check if you have a lipoma by looking for the following:

• Soft and squishy feeling
• Move under the skin if you press them
• Painless
• Slow growth
• Varying sizes from ‘pea size’ to a few centimetres wide.⁴

Some lipomas, such as angiolipomas, can be painful as they contain blood vessels. 

A liposarcoma is rapidly growing fatty tissue that develops into a cancerous tumour.⁵ They are usually painful and do not move under the skin. A clinician would be able to differentiate this from a non-cancerous (benign) lipoma. 

Management and treatment for lipoma

As mentioned before, lipomas do not require treatment; however, they can be surgically removed as a same-day outpatient procedure or at a private clinic.³

Diagnosis

The following are used to diagnose a lipoma:

• X-ray, MRI or CT for size, depth and appearance of the growth
• Biopsy - removal of tissue for lab examination
• Physical examination⁵

Very rarely can a lump in the skin indicate a more sinister diagnosis, such as cancer, but this would be ruled out with further scans and tests under the supervision of a clinician. 

FAQs

How can I prevent lipoma?

Lipomas cannot be prevented if they are hereditary; however, if they are caused by conditions such as Madelung’s disease, you could reduce the risk by lowering your alcohol consumption.³

How common is a lipoma

Around 1 in 100 people (1%) will develop a lipoma.² Risk factors such as genetics and certain conditions can increase the likelihood. 

Who is at risk of a lipoma?

Lipomas typically develop in people aged 40-60.⁶ There is no gender bias reported to date, although specific types of lipomas are seen more frequently in particular age groups. For example, children from the age of 3 onwards are more likely to develop lipoblastomas and lipomatosis.⁶

Multiple lipomas are present in around 5% of people.⁶

When should I see a doctor?

You should see a doctor if:

• The lump is painful, red or warm to the touch ⁴
• The lump does not move and is not squishy
• Multiple lumps across different sites of the body

Summary

Lipomas are harmless and do not require treatment. If you are unsure if a growth is a lipoma, a clinician would be able to tell and use scans or imaging tests to confirm a diagnosis.