Dermatofibroma: an abortive immunoreactive process mediated by dermal dendritic cells?

Dermatofibromas are very common tumors of the skin, but little is known about their etiology and pathogenesis. Current concepts of disease pathogenesis are discussed, with special emphasis on an immunoreactive origin. There is recent evidence, that high numbers of cells with dendritic morphology and positive staining for factor XIIIa are concentrated at the periphery of the lesions. Furthermore, they express MHC class II molecules and costimulatory molecules such as B7-1 and B7-2 on their surface. Thus, there are similarities to professional antigen-presenting cells of the dendritic cell family, so-called dermal dendritic cells (DDCs), which have recently been identified in the human dermis. A concept is developed which explains DF as an abortive immunoreactive process, featuring DDCs as initiators of the disease.