Benign fibrous histiocytoma

Dermatofibroma
Classification and external resources
Specialty
ICD-10	D23 (ILDS D23.L62)
ICD-9-CM	216.9
ICD-O	M8830/0
DiseasesDB	29384
eMedicine	derm/96
Patient UK	Benign fibrous histiocytoma
MeSH	D018219

Benign fibrous histiocytomas (also known as Dermal dendrocytoma, Dermatofibroma, Fibrous dermatofibroma, Fibrous histiocytoma, Fibroma simplex, Nodular subepidermal fibrosis, and Sclerosing hemangioma) are benign skin growths.

Presentation

Dermatofibromas are hard solitary slow-growing papules (rounded bumps) that may appear in a variety of colours, usually brownish to tan; they are often elevated or pedunculated. A dermatofibroma is associated with the dimple sign; by applying lateral pressure, there is a central depression of the dermatofibroma. Although typical dermatofibromas cause little or no discomfort, itching and tenderness can occur. Dermatofibromas can be found anywhere on the body, but most often they are found on the legs and arms. They occur most often in women; the male to female ratio is about 1:4. The age group in which they most commonly occur is twenty to forty-five years.

Some physicians and researchers believe dermatofibromas form as a reaction to previous injuries such as insect bites or thorn pricks. They are composed of disordered collagen laid down by fibroblasts. Dermatofibromas are classed as benign skin lesions, meaning that they are completely harmless, though they may be confused with a variety of subcutaneous tumours. Deep penetrating dermatofibromas may be difficult to distinguish, even histologically, from rare malignant fibrohistocytic tumours like dermatofibrosarcoma protuberans.

Immunohistochemical staining

Neoplasm	CD34	Stromelysin-3	Factor XIIIa
Dermatofibroma	-	+	+
Dermatofibrosarcoma protuberans	+	-	-

See also

• Dermatology
• Seborrheic keratosis
• Acrochordon, also called skin tags
• List of cutaneous conditions