A dermatofibroma is a round, brownish to purple growth on body surface. It is commonly found on the legs and arms. A dermatofibroma is also sometimes called a fibrous histiocytoma. It is due to a non-cancerous growth of dermal dendritic histiocyte cells. Dermatofibromas contain scar tissue and feel like hard lumps in the skin. Their size does not exceed 5 mm. They are mostly red or red-brown but can also be blue-black due to the deposit of haemosiderin.
Some physicians and researchers believe dermatofibromas form as a reaction to previous injuries such as insect bites or thorn pricks.
The cause of dermatofibromas is unknown. The main cause of the Dermatofibroma is insect bites, minor injury or thorn pricks. It occurs both male and female. But from the research it is found that it is mostly occurs in female. The ratio of male to female affected by this is 1:4. It is rarely found in children.
A dermatofibroma is of cosmetic significance only and although it tends to persist long term, it seldom causes any symptoms. Sometimes its dark colour can raise anxiety about melanoma; if there is any doubt about its nature, the lesion can be excised for histology.
Cutaneous fibrous histiocytomas are divided into dermatofibroma and histiocytoma. When the tumor is located in the skin, fibrous histiocytoma is also called Dermatofibroma. If the skin over a dermatofibroma is squeezed a dimple forms, indicating tethering of the skin to the underlying fibrous tissue.
Dermatofibromas usually develop slowly. These small, hard, raised skin growths:
- Usually appear on the lower legs, but may appear on the arms or trunk
- May be red, pink, purplish, gray or brown and may change color over time
- May be as small as a BB pellet but rarely grow larger than a fingernail
- Are often painless but may be tender, painful or itchy
- Usually dimple inward when pinched
Dermatofibroma should better be ignored. In case the diagnosis is not certain a piece can be removed for tissue examination.
Treatment of dermatofibromas should be considered when they get in the way of shaving or become irritated by clothing. In these cases surgical shaving of the top, punching out the center and maybe freezing with liquid nitrogen can be done.
Dermatofibromas do not go away by themselves. However, treatment of dermatofibromas is usually not necessary unless they are causing you some discomfort (itching or pain) or you feel they are unattractive. Dermatofibromas do not pose any risk to your health. If there is doubt about the diagnosis, the bump can be surgically removed under local anesthesia (medicine just numbs the area of surgery to prevent pain) and examined more thoroughly under a microscope (a biopsy)