Lipoma

A lipoma is a slow-growing, fatty lump that's most often located between your skin and the underlying muscle layer. It feels doughy and moves easily with slight finger pressure.  

Types & Stages 

There are several types of lipomas, including:

• Angiolipoma. This type contains fat and blood vessels and are often painful.
   
• Conventional. The most common type, a conventional lipoma contains white fat cells, which store energy.
   
• Fibrolipoma. This type is made up of fat and fibrous tissue.
   
• Hibernoma. This kind of lipoma contains brown fat cells, which help regulate body temperature.
   
• Myelolipoma. These lipomas contain fat and tissues that produce blood cells.
   
• Spindle cell. The fat cells in these lipomas are longer than they are wide.
   
• Pleomorphic. These lipomas have fat cells of various sizes and shapes.

Signs & Symptoms 

Lipomas can occur anywhere in the body. Many people who have a lipoma don’t notice any symptoms. They tend to:

• Commonly occur in the areas of the neck, shoulders, back, abdomen, arms and thighs
• Be soft and doughy to the touch  
• Move easily with slight finger pressure
• Be generally small (lipomas are typically less than 1 to 2 inches in diameter, but they can grow)
• Be painful if they grow and press on nearby nerves or if they contain many blood vessels

Diagnosis 

Tests and procedures to diagnose a lipoma may include:

• Imaging tests. These may include:  
   
  • X-rays. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
     
  • Ultrasound. A medical imaging technique that uses high-frequency sound waves to create real-time pictures of the body's internal organs, soft tissues and blood flow.
     
  • Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body.  
     
  • Computerized tomography scan (CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. If the lipoma is large, has unusual features or appears to be deeper than the fatty tissue. 
     
• Biopsy. A procedure to remove some cells for testing. The sample might be removed with a needle put through the skin. Or the sample might be taken during surgery to remove the cancer. The type of biopsy depends on the cancer's location.

There's a very small chance that a lump looking like a lipoma may be a cancer called liposarcoma. Liposarcomas are cancerous tumors in fatty tissues. They grow rapidly, don't move under the skin and often are painful. A biopsy, or an MRI or CT scan, is typically done if your doctor suspects liposarcoma.

Treatment 

A lipoma typically doesn't need to be treated unless it’s uncomfortable, painful or growing. Lipoma treatments include:

• Surgical removal. Most lipomas are removed surgically by cutting them out. Lipomas typically don't return once they're removed. A technique known as minimal excision extraction may result in less scarring.
   
• Liposuction. This treatment uses a needle and a large syringe to remove the fatty lump.

Causes & Risk Factors 

There are factors may raise your risk of getting a lipoma, including:

• Age. Although lipomas can occur at any age, they're most common between 40 and 60 years old.  
   
• Genetics. Lipomas tend to run in families. Conditions include:  
   
  • Dercum’s disease. This rare disorder causes painful lipomas to grow, most often on the arms, legs and trunk. It’s also called adiposis dolorosa or Anders’ syndrome.
     
  • Gardner syndrome. A form of a disorder called familial adenomatous polyposis (FAP), Gardner syndrome causes lipomas and a range of health problems.
     
  • Hereditary multiple lipomatosis. Also called familial multiple lipomatosis, this disorder is passed down through families.
     
  • Madelung’s disease. This condition occurs most often in men who drink alcohol excessively. Also called multiple symmetric lipomatosis, Madelung’s disease causes lipomas to grow around the neck and shoulders.

Screening 

There is no routine screening for lipomas.