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Dermatofibroma (histiocytoma)

DERMATOFIBROMA (ALSO KNOWN AS HISTIOCYTOMA)

What are the aims of this leaflet?

This leaflet has been written to help you understand more about dermatofibromas. It explains what they are, what causes them, what can be done about them, and where you can find out more about them.

What is a dermatofibroma?

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 benign (harmless) and will not turn into a cancer. Whilst dermatofibromas are harmless, they can be similar in appearance to other concerning skin tumours. It is therefore important to see a health professional for a diagnosis.

What causes a dermatofibroma to appear?

The exact cause of dermatofibroma is not clear. However, they often seem to appear after a minor injury to the skin such as a prick from a thorn or an insect bite. Certain patient groups can be more prone to developing dermatofibromas.

Are dermatofibromas hereditary?

There is no evidence to suggest that dermatofibromas are hereditary.

What are the symptoms of a dermatofibroma?

Usually there are no symptoms, but some people may be concerned about their appearance. Occasionally dermatofibromas can itch or become painful when touched or knocked. If they are on the legs, shaving the skin over them can cause bleeding.

What do dermatofibromas look like?

  • A firm bump that feels like a small rubbery button lying just under the surface of the skin, seldom larger than 1 cm in diameter.
  • They can vary in colour from purple to pink and can sometimes appear brown or grey.
  • A dimple may appear over a dermatofibroma when pinched.
  • They can appear anywhere but are most common on the lower legs of young to middle-aged adults, and on the upper arms in females.
  • It is not known why, but dermatofibromas are more common in females compared to males.

Will I get more than one dermatofibroma?

Most people with a dermatofibroma will have only one. However, rarely some individuals develop multiple dermatofibromas in a short period of time; this can be due to underlying immunosuppression caused by medication, or diseases such as lupus, HIV, and rarely certain cancers. If in doubt, seek medical advice.

How is dermatofibroma diagnosed?

A doctor can usually identify a dermatofibroma easily by its appearance. However, if there is doubt about the diagnosis or concern over the possibility of skin cancer, it can be removed under a local anaesthetic and looked at under a microscope.

What are the treatment options for dermatofibroma?

Dermatofibromas sometimes disappear without any treatment, although in many cases they can last indefinitely. Because they are harmless treatment is not usually necessary other than an accurate diagnosis and reassurance.

Treatment of dermatofibroma is often not available within the NHS but may be appropriate if:

  • There is any doubt about the diagnosis.
  • It is unsightly, although you will have a scar in its place.
  • It is causing symptoms such as itching or pain.  Although these symptoms may cease with time, and the scar after removal may also be itchy or painful.

Treatment options include:

  • Intra-lesional steroid injections (steroid injections into the lesion), which can cause the dermatofibroma to flatten slightly.
  • Cryotherapy (freezing with liquid nitrogen), but this will leave a scar and the lesion may recur.
  • Some lasers, including carbon dioxide lasers (which work to flatten the lesion) and pulsed dye lasers (which target the blood supply to the lesion) have shown good results but may also scar.
  • Excision (surgical removal) under local anaesthetic. This will always leave a scar, which may be as troublesome as the original lesion.

What can I do if I think I have a dermatofibroma?

Anyone who develops a new lump on their skin, particularly if it is pigmented, should seek the advice of their doctor or health professional for a formal diagnosis.

Where can I get more information?

Links to other Internet sites:

http://dermnetnz.org/lesions/dermatofibroma.html

http://www.patient.co.uk/doctor/Dermatofibroma.htm

For details of source materials used please contact the Clinical Standards Unit (clinicalstandards@bad.org.uk).

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED DECEMBER 2007
UPDATED DECEMBER 2010, NOVEMBER 2013, JANUARY 2017, JANUARY 2020
REVIEW DATE JANUARY 2023

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