A dermatofibroma is a round, brownish to red-purple growth commonly
found on the legs. It is also called a histiocytoma. It can occur
anywhere, but seems to favor exposed areas. Dermatofibromas feel like
hard lumps under the skin. They are iceberg-like in that there is more
under the skin than seen on the surface. They often start out red, and
sometimes itch. They usually turn brown later. They probably are a
reaction to a minor injury, such a bug bite or a splinter.
We do know that they are harmless and never turn cancerous. For
this reason, they are best ignored. If the diagnosis is uncertain, a
biopsy may be taken for confirmation. Usually, complete surgical
removal leaves a scar that is worse than the Dermatofibroma.
Treatment of dermatofibromas should be considered when they get in
the way of shaving, become irritated by clothing, or there is a
concern that the growth is a skin cancer and not a dermatofibroma. In
these cases surgical "shaving" of the top,
"punching" out the center and maybe freezing with liquid
nitrogen can be done. These treatments only destroy the upper part of
the growth, and after a few years it may again become noticeable. If
this happens, the treatment could be repeated again if desired.
If you have a growth thought to be a dermatofibroma that grows or
bleeds, or if you are concerned that it may be a skin cancer the
growth should be biopsied.