Answer:
Dermatofibroma, histiocytoma, nodular subepidermal fibrosis, fibroma simplex, sclerosing hemangioma, noduli cutanei, and fibroma durum are various terms that have been applied to a common benign nonencapsulated, reactive, lenticular intradermal nodular lesion composed of proliferating fibrocytes, irregularly arranged bundles of fine collagen fibers, capillary blood vessels, histiocytes, and mononuclear inflammatory cells in varying proportions. At times the histiocytes in the lesions accumulate hemosiderin or become somewhat xanthomatized. The lesions are firm and range in color from pale skin hues through various shades of red, brown, and yellow. They occur most often on the lower extremities but also are seen on the arms and trunk in adults. They rarely exceed 1 cm to 2 cm in size. It is believed that some of these lesions develop at sites of minor trauma, for example, mosquito bites. No treatment is usually needed unless excision becomes warranted for cosmetic or symptomatic reasons. Excision for histologic establishment of the diagnosis may be necessary. Incomplete removal tends to be followed by recurrence.
Dermatofibrosarcoma protuberans usually presents as a slowly growing, hard, nodular protuberant mass arising in the dermis, mostly on the trunk and thighs. It may be erythematous or slightly dusky in color and is covered by smooth, shiny epithelium that gives a keloidal appearance. There may be complicating ulceration, infection, and scarring. As this local disorder becomes extensive, it may cause severe pain, contractures, and invalidism. Histologically, there is a characteristic “cartwheel” pattern of the hypercellular fibrous bundles in these nonencapsulated tumors that extend finger-like processes into adjacent subcutis and fascia. Mitotic figures may be numerous. Wide excision, including the deep fascia, is necessary to prevent recurrence. Surgical margins of up to 3 cm have been recommended in the literature. Long-standing, inadequately excised lesions have been known to metastasize