Dermatofibroma

Published by Bupa's Health Information Team, July 2010.

This factsheet is for people who have a dermatofibroma, or who would like information about it.

A dermatofibroma is a type of non-cancerous growth in the skin. It's also known as a histiocytoma.

About dermatofibromas

A dermatofibroma feels like a small hard lump under your skin. It's an abnormal growth consisting of cells, blood vessels and scar tissue, which develops in a layer of your skin called the dermis. A dermatofibroma is harmless and isn't a type of cancer.

The structures and layers of the skin

Dermatofibromas are more likely to affect women than men, and tend to develop in young to middle-aged adults. They are most likely to appear on your lower legs - although they can occur anywhere on your body. Most people who have a dermatofibroma only have one, although some people may get several.

Symptoms of dermatofibroma

If you have a dermatofibroma, the lump may:

• appear gradually, usually over several months
• be 5mm to 10mm across, rarely more
• have a dull, shiny or scaly surface
• range from pink to brown in colour

A dermatofibroma doesn't usually cause symptoms. However, it may hurt or itch if you touch or knock it.

If you notice any new lump on your skin, contact your GP for advice.

Causes of dermatofibroma

The exact reasons why you may develop a dermatofibroma aren't fully understood at present. However, a dermatofibroma often seems to develop after you have had a minor injury to your skin, such as from a thorn or an insect bite.

Diagnosis of dermatofibroma

Your GP will examine the lump on your skin and may also ask about your medical history.

Your GP will usually be able to identify that the growth is a dermatofibroma from the way it looks. If your GP is unable to confirm your diagnosis, he or she may refer you to a dermatologist. A dermatologist is a doctor who specialises in skin conditions. If there is any doubt about your diagnosis, your dermatologist may suggest that you have a skin biopsy - this means a sample of your skin is taken and sent to a laboratory for testing.

Treatment of dermatofibroma

As dermatofibromas are harmless and usually cause little trouble, it's likely that you won't need any treatment at all. Your GP will be able to reassure you if you have any concerns about your dermatofibroma.

However, your GP may recommend that you have your dermatofibroma removed with minor surgery if:

• it's causing you symptoms such as pain or itching
• there is any doubt about your diagnosis

Surgery

Your GP may be able to carry out minor surgery to remove your dermatofibroma in his or her surgery. Alternatively you may be referred to a dermatologist at your local hospital, where you will have the procedure as an outpatient.

Before the procedure, your doctor will clean your skin around the dermatofibroma and give you a local anaesthetic. This will numb the affected area of your skin. Your doctor will remove the growth using a surgical knife (scalpel) to cut into your skin. He or she will then close your wound with stitches.

Surgery to remove a dermatofibroma always leaves a scar, which unfortunately can be as noticeable as the dermatofibroma itself. Your doctor will discuss this with you, and can help you to decide whether or not to have the procedure.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.