Lumps under the Skin (Lipoma)

What is a lipoma?

A lipoma is an oval or round-shaped tissue mass that forms under the surface of the skin. It consists of fat, slides easily when touched, and is usually painless. While these growths can develop on any part of the body, they most commonly appear on the back, arms, torso (trunk), neck, and shoulders.

Lipomas are non-cancerous soft tissue tumours that grow gradually over time. Most cases do not require any treatment, but if they cause discomfort, they can be removed through a simple outpatient surgical procedure.

How common are lipomas?

Lipomas are relatively common, occurring in nearly 1 out of every 1,000 people. Although they most often develop in individuals aged 40 to 60, they can appear at any age and occasionally exist from birth. Everyone, regardless of gender, can develop lipomas, but women are slightly more likely to be affected than men.

Types of lipomas

Most lipomas consist of fat, though some also contain blood vessels or other types of tissues. Common types of lipomas include:

• Angiolipoma: Made of fat and blood vessels, these are often painful.
• Conventional: The most prevalent type, composed of white fat cells that store energy.
• Fibrolipoma: Comprised of fat and fibrous tissues.
• Hibernoma: Contains brown fat, whereas most lipomas contain white fat. Brown fat cells produce heat and help regulate body temperature.
• Myelolipoma: Composed of fat and blood cell-producing tissue.
• Spindle cell: Characterised by fat cells that are longer than they are wide.
• Pleomorphic: Contains fat cells of varying shapes and sizes.

Symptoms

What are the symptoms of a lipoma?

Lipomas are generally painless, although they can cause discomfort if they press on a nerve or are located near a joint. Most people with a lipoma do not experience any symptoms. Common characteristics of these lumps under the skin include:

• Encapsulated: They do not spread to surrounding tissues.
• Painless: However, some lipomas can be painful, depending on their size, location, and whether blood vessels are involved.
• Moveable: Situated just beneath the surface of the skin, they move easily when touched.
• Round or oval-shaped: These fatty lumps are symmetrical and feel rubbery.
• Smaller than 2 inches in diameter: In some cases, lipomas can grow larger than 6 inches.

Where do lipomas develop?

Lipomas can occur in any part of the body, though they rarely develop in the brain, internal organs, or muscles. While most people with lipomas have only one, some may develop multiple lipomas.
Lipomas commonly form just beneath the skin in the following areas:

• Back
• Neck
• Shoulders
• Arms or legs
• Forehead
• Trunk (chest and torso)

Causes

What causes a lipoma?

The exact causes of lipomas are not well understood. However, they are often hereditary, meaning they run in families. You are more likely to develop a lipoma if a family member has one. Certain conditions can also trigger the formation of multiple lipomas, including:

• Dercum’s disease: A rare condition that causes painful lipomas, usually affecting the trunk, legs, and arms. It is also known as adiposis dolorosa or Anders’ syndrome.
• Gardner syndrome: A condition that is a type of familial adenomatous polyposis (FAP), contributing to the growth of lipomas and other health issues.
• Hereditary multiple lipomatosis: Also known as familial multiple lipomatosis, this inheritable condition is passed from parents to children.
• Madelung’s disease: Also known as multiple symmetric lipomatosis, this disorder primarily affects men who consume excessive alcohol, causing lipomas to grow around the neck and shoulders.

Diagnosis and Tests

How are lipomas diagnosed?

Lipomas are usually diagnosed during a physical examination. Your healthcare provider will feel the lump and ask if there is any pain or tenderness. To confirm the lump is a lipoma and not cancerous, a biopsy may be performed, where a small sample of the lump is analysed in a laboratory.

Lipomas are sometimes mistaken for cysts. Your doctor may recommend an imaging test, such as an ultrasound, CT scan, or MRI, to get a clearer view of the lump. These imaging studies help distinguish between a lipoma and a cyst and also provide information about the lipoma’s location, depth, involvement of blood vessels, and whether it is pressing on nearby tissues or nerves.

Management and Treatment

What is the treatment for lipomas?

In most cases, lipomas do not require treatment. However, if they cause discomfort or concern, your doctor can surgically remove them. These procedures are generally safe and effective, performed on an outpatient basis, meaning you can return home the same day.

Alternatively, your doctor might recommend liposuction to remove the lump. This procedure involves using a long, thin needle to extract the fatty tissue from the lipoma.

Prevention

Can I prevent lipomas?

Lipomas and the conditions that contribute to their formation are genetic, so prevention is not possible. However, you can reduce the risk of developing Madelung’s disease (which is associated with lipomas) by limiting alcohol intake.

Outlook / Prognosis

What is the outlook for people with lipomas?

Most people with lipomas live with the condition without any issues. Treatment is typically unnecessary, but healthcare providers can remove the lumps if needed. Once a lipoma is removed, it rarely grows back in the same place, though new lipomas may form elsewhere on the body.

Living With

When should I see my doctor about lipomas?

If you notice a growth, lump, or knot under your skin, it’s important to visit your healthcare provider to rule out serious conditions like liposarcoma, a type of cancer that can resemble lipomas.
If you already have a lipoma, see your doctor if it suddenly becomes painful, enlarges rapidly, feels hard, or becomes less moveable when touched. Your doctor will check if it contains blood vessels, which could indicate a rare, painful type of lipoma called an angiolipoma.

A Note from MD.co.uk

Many people live with lumps under their skin, which are often harmless. While lipomas can be unsightly or bothersome, they usually do not cause significant problems. Most lipomas do not require treatment, but if one becomes uncomfortable or you are concerned about its size or location, it’s best to contact your healthcare provider. Lipomas can often be safely removed during an outpatient procedure, and they rarely grow back afterwards.