Dermatofibromas, also known as benign fibrous histiocytomas in dermatology world, are one of the most common skin growths. They are often found on legs of adults as firm, hyperpigmented bumps, usually less than a cm in diameter. Although, presence on arms and trunk, and growths bigger than 3 cm have been described. They are believed to be a result of trauma or insect bites that cause harmless growth of cells called fibroblasts in the deeper layer of skin.
These growths are usually asymptomatic, but may be itchy or irritated if traumatized or when shaved. They are diagnosed clinically and have a characteristic sign of dimpling when pinched.
A skin biopsy may be required if the diagnosis is uncertain or if there are changes or symptoms. Sometimes, skin cancers can mimic normal growths and biopsy will help differentiate from basal cell cancers, keratoacanthoma and dermatofibrosarcoma protuberans (DFSP).
Usually, no treatment is required unless the growth is symptomatic. Surgical excision is done for changing or bleeding lesion or when the growth is suspicious for malignancy. Cosmetic removal can be done when requested, however, it is highly discouraged because the scar can look worse than the initial growth, especially on the lower extremities. Also, surgical treatments on legs often get infected. So extra precautions should be taken during the healing time after procedures on legs. Liquid nitrogen cryotherapy is another treatment option for lesions that protrude above the skin surface and or when irritated from repeated trauma with good flattening of lesions.