Typically, a dermatofibroma feels like a firm, pea-sized, buttonlike papule that is fixed to the surrounding dermis (accounting for the “dimple” or “collar button” sign) (Fig. 30.39A,B).
Also known as fibrous histiocytoma and sclerosing hemangioma, a dermatofibroma (DF) is a common dermal fibrous tumor of unknown cause.
DFs occur most commonly on the legs, trunk, and arms, especially in women older than 20 years of age. The lesions are benign growths that are usually brought to medical attention either to rule out skin cancer or because of cosmetic concerns.
A lesion may be a papule or a nodule. It may be elevated with a dome shape, flat, or depressed below the plane of the surrounding skin (Fig. 30.38).
The color can vary, even in a single lesion, and can appear as skin-colored, chocolate brown, red, or even purple.
The surface may be smooth or scaly, depending on whether the lesion has been traumatized (e.g., by shaving).
Typically, a dermatofibroma feels like a firm, pea-sized, buttonlike papule that is fixed to the surrounding dermis (accounting for the “dimple” or “collar button” sign) (Fig. 30.39A,B).
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