The biopsy specimen showed epidermal acanthosis and increased cellularity in the dermis, with a proliferation of stellate fibroblastlike cells. There was an increase in collagen throughout the lesion. The results of staining for factor XIIIa antigen were positive.
Dermatofibromas, also known as sclerosing hemangioma, subepidermal nodular fibrosis, or histiocytomas, are thought to arise as a result of a stimulus to the skin, such as an insect bite, although this theory has recently been challenged.1 It has been proposed that the dermatofibroma may be a tumor of the dermal dendrocyte.2
Multiple Nodules on the Back. Arch Dermatol. 1999;135(3):341-b-346. doi:10-1001/pubs.Arch Dermatol.-ISSN-0003-987x-135-3-dof0399