A dermatofibroma is a common, noncancerous, button-like, 3 mm to 10 mm brown bump (papule), frequently seen on the lower extremities. They grow more rapidly than moles--over a few months. Also called a fibrous histiocytoma. The cause is unknown but current thinking suggests that they develop from minor trauma like an insect bite. If removed and analyzed microscopically, dermatofibromas are found to contain very dense collagen. There is no pressing need to remove them.
A dermatofibroma consists of a proliferation of scar-like tissue within the deeper layers of the skin.
CAUSES
The right cause of dermatofibroma is unknown. They are usually single but sometimes may be multiple. Here are Dermatofibroma causes may include :-
* Insect Bite
* Folliculitis
* Idiopathic benign skin tumor
SIGNS
Dermatofibroma most often occur on the legs and arms. Once developed, they usually persist for years. They appear as firm-feeling nodules, often yellow-brown in colour, sometimes quite dark, especially in dark coloured skin. Dermatofibromas feel like hard lumps under the skin. If the skin over a dermatofibroma is squeezed a dimple forms, indicating tethering of the skin to the underlying fibrous tissue.
SYMPTOMS
Often Dermatofibroma start out as red, turning later to brown, and sometimes itch. They probably are a reaction to a minor injury, such a bug bite or a splinter. Dermatofibromas usually develop slowly and usually appear on the lower legs. These small, hard, raised skin growths can have various characteristics:
* Usually found on the lower legs, but may appear on the arms or trunk
* Small firm Papule, Plaque or Nodule
* May be red, pink, purplish, gray or brown and may change colors over time
* May be as small as a BB pellet but rarely grow larger than a fingernail
* Often painless but may be tender, painful or itchy
* Usually dimple inward when pinched.
* Skin dimples downward with lateral compression
DIAGNOSIS
Most often, a physician can diagnose a dermatofibroma by examining the nodule. If the growth does not look like a typical dermatofibroma, if a bleeding sore appears on its surface, or if the physician wants to be certain of the diagnosis, he or she performs a biopsy. A biopsy removes either a portion or all of the nodule for examination under a microscope. Some of differential diagnosis are :-
* Primary Malignant Melanoma
* Blue Nevus
* Scar
TREATMENT
Dermatofibromas do not require treatment because they do not pose any risk. Some patients may prefer to have their dermatofibromas removed because when dermatofibromas get in the way of shaving or become irritated by clothing. Here are some removal methods of dermatofibroma:
* 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.
* Dermatofibroma are best ignored. If the diagnosis is uncertain, a piece may be removed for tissue analysis.
* Dermatofibroma can be removed surgically, but since they are deep, this usually leaves a scar.
* 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.
PROCEDURES
* Surgically.
* Freezing.
Because a dermatofibroma grows deep, total surgical removal requires cutting it out below the surface level of the skin. This process usually leaves a noticeable scar. Alternatively, the nodule may be flattened to the surface of the skin by shaving the top off with a surgical knife or by freezing it with liquid nitrogen. In both of these procedures, the top layers of the dermatofibroma are destroyed, but the deeper layers remain. The nodule may grow back again after several years. If a growth that was thought to be a dermatofibroma grows or bleeds, or if there is any concern that it may be a skin cancer, the growth should be biopsied.
