(Histiocytoma, Benign Fibrous Histiocytoma)
A dermatofibroma is an extremely common, small, firm bump on the skin, which represents an overgrowth of the tissue lying between the outer and inner layers of skin. They are generally pinkish-brown in color and are often found on the legs. They usually occur alone and have no symptoms whatsoever. Sometimes more than one appears. Generally, dermatofibromas are harmless and have no connection to skin cancer.
The cause of dermatofibromas is unknown. They sometimes seem to appear after a minor injury to the skin such as an insect bite or a prick of a thorn.
A risk factor is something that increases your chances of getting a disease or condition. The following factors increase your chances of developing dermatofibromas:
- Sex: Women are more likely to develop this condition than men
- Age: Middle-aged adults (dermatofibromas are rarely found in children)
Dermatofibromas are generally cause no symptoms. However, it is always important to see a physician about any new skin growth.
- Usually reddish-brown in color
- They are darker for individuals with darker skin
- The color may change over time
- Found most often on the legs, but may also appear on the arms or trunk of the body
- Small in size (3–10 millimeters)
- Occasionally itchy or sensitive when touched
- Raised from the skin and may bleed if damaged (e.g., if you shave over a dermatofibroma it can bleed)
Your doctor will ask about your symptoms and medical history, and perform a physical exam.
A dermatofibroma is diagnosed by sight. Your doctor will look at the bump and will most likely be able to identify it by the way it looks. Your doctor may also squeeze the skin over the dermatofibroma. When squeezed together, a dimple will form.
If there is doubt about the diagnosis, the bump can be surgically removed under local anesthesia (medicine just numbs the area of surgery to prevent pain) and examined more thoroughly under a microscope (a biopsy).
Dermatofibromas do not go away by themselves. However, treatment of dermatofibromas is usually not necessary unless they are causing you some discomfort (itching or pain) or you feel they are unattractive. Dermatofibromas do not pose any risk to your health.
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
The dermatofibroma may be cut off surgically under local anesthesia. Keep in mind that because the dermatofibroma is usually deep, removal of the dermatofibroma will always leave a scar that may not be any more attractive than the dermatofibroma itself.
Liquid nitrogen can be used to freeze the bump and flatten it out. This method usually leaves a white mark behind. Also, the dermatofibroma may eventually grow back.
There is no way to prevent dermatofibromas.