Definition

A dermatofibroma is an very common skin growth. It is a small, firm bump on the skin. The dermis layer of skin contains nerve endings, glands, and vessels. The bump is an overgrowth of the tissue in the dermis layer. The bump is generally pinkish-brown in color. It is often found on the legs. Sometimes more than one appears. Generally, they are harmless and are not connected to skin cancer.

Causes

The cause is unknown. Dermatofibromas sometimes appear after a minor injury to the skin. This can include an insect bite or a prick of a thorn.

Risk Factors

The following factors increase your chance of developing dermatofibromas:

• Sex: women are more likely to develop this condition than men.
• Age: adults (dermatofibromas are rarely found in children)

Symptoms

These bumps rarely cause symptoms. However, it is always important to see a doctor about any new skin growth.

Dermatofibromas are:

• Usually reddish-brown in color
  • Are darker in individuals with darker skin
  • May change color over time
• Found most often on the legs, but may also appear on the arms or torso of the body
• Small in size (3-10 millimeters)
• Very firm to touch
• Sometimes itchy or sensitive when touched
• Raised from the skin and may bleed if damaged (eg, a dermatofibroma can bleed if you shave over it)

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done.

A dermatofibroma is diagnosed by sight and touch. Your doctor may also squeeze the skin over the bump. When squeezed together, a dimple will form.

If diagnosis is not certain, the bump can be surgically removed. The removed tissue will be examined under a microscope.

Treatment

Dermatofibromas do not go away by themselves. Treatment is usually not necessary. It may be done if they are causing you some discomfort (itching or pain) or you feel they are unattractive. They do not pose any risk to your health.

Talk with your doctor about the best plan for you. Treatment options include the following:

Prevention

There is no way to prevent dermatofibromas.

British Association of Dermatologists http://bad.org.uk

Dermatologists.ca http://www.dermatologists.ca

Dermatofibroma. New Zealand Dermatological Society website. Available at: http://dermnetnz.org/lesions/dermatofibroma.html . Accessed November 16, 2012.

Prieto VG, Reed JA, Shea CR. Immunohistochemistry of dermatofibromas and benign fibrous histiocytomas. J Cutan Pathol . 1995;22(4):336-341.