[Elastosis perforans serpiginosa. Considerations on the pathogenesis based on a typical case].

Elastosis perforans serpiginosa (EPS) is a rare entity belonging to the group of primary perforating dermatoses. A 13-year-old male patient with Down's syndrome developed reddish hyperkeratotic papules in a serpiginous and ellipsoid configuration on the face. Histological examination revealed transepidermal elimination of thick coarse elastic fibres from the papillary dermis. The dermal infiltrate showed an immunohistological pattern consistent with an acute cell-mediated immune response. It consisted mainly of activated T-lymphocytes, with a predominance of CD4-positive cells. Considerable numbers of CD1-positive cells were also present. Inflammatory macrophages of the 27E10 phenotype were found in considerable numbers, whereas 25F9-positive resident macrophages were almost completely absent. The role of a cell-mediated immune response in the mechanism of transepithelial elimination is discussed.