What is a lipoma?
A lipoma is a non-cancerous tumour that is made up of fat cells. It slowly grows under the skin in the subcutaneous tissue. A person may have a single lipoma or may have many lipomas. They are very common.
Who gets lipomas?
Lipomas can occur in people of all ages, however, they tend to develop in adulthood and are most noticeable during middle age. They affect both sexes equally, although solitary lipomas are more common in women whilst multiple lipomas occur more frequently in men.
What causes a lipoma?
The cause of lipomas is unknown. It is possible there may be genetic involvement as many patients with lipomas come from a family with a history of these tumours. Sometimes an injury such as a blunt blow to part of the body may trigger the growth of a lipoma.
What are the signs and symptoms of lipoma?
People are often unaware of lipomas until they have grown large enough to become visible and palpable. This growth occurs slowly over several years. Some features of a lipoma include:
- A dome-shaped or egg-shaped lump about 2–10 cm in diameter (some may grow even larger)
- It feels soft and smooth and is easily moved under the skin with the fingers
- It may have a rubbery or doughy consistency
- Lipomas are most common on the shoulders, neck, trunk and arms, but they can occur anywhere on the body where fat tissue is present.
Most lipomas are symptomless, but some are painful when applying pressure. A lipoma that is tender or painful is usually an angiolipoma. This means the lipoma has an increased number of small blood vessels. Painful lipomas are also a feature of adiposis dolorosa or Dercum disease.
How is the diagnosis of lipoma made?
Diagnosis of lipoma is usually made clinically by finding a soft lump under the skin. However, if there is any doubt, a deep skin biopsy can be performed which will show typical histopathological features of lipoma and its variants, such as a hibernoma.
The rare fatty cancer, liposarcoma, almost never arises in the skin. Liposarcoma is a deep-seated tumour, and most often grows on thigh, groin or at the back of the abdomen. If your lipoma is enlarging or becomes painful, check with your doctor. A skin biopsy may be required to exclude liposarcoma.
What treatment is available?
Most lipomas require no treatment. They eventually stop growing and persist without causing any problems. Occasionally, a lipoma that interferes with the movement of adjacent muscles may require surgical removal. Several methods are available:
- Simple surgical excision
- Squeeze technique (a small incision is made over the lipoma and the fatty tissue is squeezed through the hole)