Dermatofibromas (also known as histiocytomas) are common benign fibrous skin lesions. They are caused by the abnormal growth of dermal dendritic histiocyte cells, often following a precipitating injury. Common areas include the arms and legs.
Features
Dermatofibroma on the dorsum of the hand. Asymptomatic, firm, dome-shaped nodule.
Dermatofibroma on the left calf of a middle-aged man.
This image shows the 'pinch test'. A dimple is formed when a dermatofibroma is pinched indicating tethering of the skin to the underlying fibrous tissue