Lipoma

Symptoms

• A soft, dome-shaped or egg-shaped lump located just under the skin.
• Feels soft and 'doughy' when touched.
• Moves easily with gentle finger pressure.
• Most commonly found on the neck, shoulders, back, abdomen, arms, and thighs.
• Typically small, usually less than 5 centimeters (about 2 inches) in diameter.
• Usually painless.
• Pain, especially if the lipoma grows and presses on nearby nerves or contains many blood vessels (called an angiolipoma).
• Can occasionally grow larger than 5 centimeters, sometimes referred to as 'giant lipomas'.
• Can grow deeper within muscles or organs, which might cause unusual symptoms depending on its location.
• A lipoma that feels hard or is fixed (not mobile) under the skin is atypical and requires further medical evaluation.
• Rapid growth of the lump.
• The lump becomes painful.
• The lump is larger than 5 centimeters.
• The lump feels firm or hard, rather than soft and doughy.
• The lump is fixed to underlying tissues and does not move.
• The lump is located deep within the body, such as within a muscle.
• The lump returns after it has been surgically removed.

Causes & Risk Factors

• Specific genetic changes, particularly involving chromosome 12, are found in many lipomas.
• Inherited conditions, such as Familial Multiple Lipomatosis, Gardner's syndrome, Madelung's disease, and Adiposis dolorosa (Dercum's disease), which are passed down through families, can lead to multiple lipomas.
• The exact reason why most single lipomas develop is often unknown.
• The most accepted idea is that lipomas are benign growths that start from a group of fat cells, often due to specific changes in chromosomes.
• Some theories suggest that a minor injury might trigger the growth of a lipoma in the affected area.
• Age: Lipomas are most common in adults between 40 and 60 years old, but they can appear at any age.
• Genetics: Certain inherited conditions are strongly linked to developing multiple lipomas, including Familial Multiple Lipomatosis, Gardner's syndrome, Madelung's disease, and Adiposis dolorosa (Dercum's disease).
• Obesity: While lipomas are made of fat, it is not definitively proven that being overweight causes them. The evidence for this link is not strong.
• Minor injury: Some evidence suggests that trauma or injury to an area might trigger a lipoma to grow there, but this link is uncertain.
• Diabetes mellitus: Some studies suggest a possible association, but this connection is not well-established.
• Hyperlipidemia (high levels of fats in the blood): An association is sometimes suggested, but the evidence is inconsistent.

Diagnosis

• Your doctor will ask about when you first noticed the lump, how quickly it has grown, if it causes any pain, and if there is a personal or family history of similar lumps or genetic conditions.
• A physical examination involves your doctor feeling the lump to assess its size, shape, consistency (how soft or firm it is), how easily it moves, and its depth under the skin. A characteristic 'slip sign' may be felt, where the edges of the lipoma slip away from the fingers.
• Most typical lipomas can be diagnosed based on a physical examination alone and do not require further tests.
• Imaging tests, such as an ultrasound, MRI (Magnetic Resonance Imaging), or CT (Computed Tomography) scan, may be recommended if the diagnosis is uncertain, the lump is large (over 5 cm), painful, growing rapidly, or located deep within the body.
• Ultrasound is often the first imaging test, showing a well-defined, fatty mass.
• MRI is considered the most accurate imaging method for distinguishing a lipoma from other growths, including cancerous ones like liposarcoma, as lipomas appear similar to normal fat on MRI scans.
• Laboratory tests are not typically needed for the diagnosis of a standard lipoma.
• The diagnosis of a lipoma is primarily made by a doctor based on its characteristic feel and appearance during a physical examination.
• A biopsy, where a small tissue sample is taken and examined under a microscope, is the gold standard for a definitive diagnosis but is usually reserved for cases with unusual features or when imaging results are unclear.
• It is important for your doctor to consider other conditions that might look similar to a lipoma, such as cysts, abscesses, or a malignant (cancerous) growth called liposarcoma.
• Current guidelines recommend an urgent referral to a specialist if a soft tissue lump has features that raise suspicion of a sarcoma, such as rapid growth, pain, a size greater than 5 cm, a firm or hard consistency, being fixed to underlying tissues, or being located deep within a muscle.

Treatment Options

• For most lipomas that are small, painless, and not causing cosmetic concern, the main approach is watchful waiting. Your doctor will advise you to monitor the lump for any changes, such as rapid growth or new pain, and to seek re-evaluation if these occur.
• Surgical removal (excision) is the standard treatment for lipomas. It is usually recommended if the lipoma is causing pain, is cosmetically bothersome, interferes with movement, is growing rapidly, or if there is any uncertainty about the diagnosis. The procedure is typically performed under local anaesthesia as an outpatient procedure, where the entire lipoma, including its surrounding capsule, is removed.
• Liposuction, a procedure that suctions out the fatty tissue, can be an alternative for removing large lipomas, especially in visible areas, to minimize scarring. However, there might be a slightly higher chance of the lipoma returning compared to standard surgical excision.
• Injections of a steroid mixture can sometimes cause localized fat cells to shrink, reducing the size of the lipoma. However, this is not a standard treatment, results can vary, and it does not completely remove the lesion. The evidence supporting this treatment is weak.

Frequently Asked Questions