A dermatofibroma is a common overgrowth of the fibrous tissue situated in the dermis (the deeper of the two main layers of the skin). It is quite harmless and will not turn into a cancer. Another name for dermatofibroma is histiocytoma.
This is not clear. However they often seem to come up after a minor injury to the skin such as a prick from a thorn or an insect bite.
Dermatofibromas is not hereditary.
Usually the only problem is with how they look. Occasionally they itch or hurt when touched or knocked. If they are on the legs, shaving the skin over them can cause bleeding.
Dermatofibromas look like
- They are firm bumps that feel like small rubbery buttons lying just under the surface of the skin. They are seldom more than 1 cm. Their colour ranges from pink to brown.
- They can crop up anywhere, but are most common on the lower legs of young or middle-aged adults and on the upper arms of women.
- Most people with a dermatofibroma will have only one; some people will have several; but it is very unusual to have large numbers of them. Women get them more often than men.
A doctor can usually identify a dermatofibroma easily by the way it looks. However, if there is doubt about the diagnosis, or worries over the possibility of skin cancer, the bump can be removed under a local anaesthetic and looked at under the microscope.
Diagnosing can be cured by removal under local anesthetic.
Dermatofibromas do not go away by themselves. However, as they are harmless and cause little trouble, no treatment is usually needed apart from an accurate diagnosis and reassurance.
Under a local anesthetic will always leave a scar, which may be as obvious as the original lump. Removal may be worthwhile if:
- The dermatofibroma is unsightly and you are prepared to swap it for a scar.
- It is a nuisance and causing symptoms such as itching or pain – though these symptoms may settle with time. There are any doubts about the diagnosis.
What you can do
Anyone who develops a new lump in their skin, particularly if it is pigmented, should ask their doctor to have a look at it.