What is this hard bump?
A dermatofibroma is a round, brownish to purple growth commonly found on the legs and arms. Dermatofibromas contain scar tissue and feel like hard lumps in the skin.

Why did I get it?
We don't know why people grow dermatofibromas. They are often the result of previous trauma. Some may be caused by insect bites. They are harmless and never turn cancerous.

How do I treat it?
Dermatofibromas are best ignored. If the diagnosis is uncertain, a piece may be removed for tissue analysis. Dermatofibromas can be removed surgically, but since they are deep, this usually leaves a scar. When a dermatofibroma gets in the way of shaving or is irritated by clothing, it can be flattened by freezing with liquid nitrogen. Liquid nitrogen freezing destroys only the upper part of the growth. Therefore, the dermatofibroma, after some years, may again become noticeable. Usually, any regrowth is slight and can be handled by another freezing.

If there is any unusual change or marked regrowth of a dermatofibroma, please call the office at (707) 725-8770.