During the past decade or so, the incidence of syphilis has increased in most parts of the world. In some urban regions, a coinfection with human immunodeficiency virus is disclosed in nearly 50% of the cases. Owing to the polymorphism of the lesions, the clinical diagnosis may be puzzling. The homing patterns and migration paths of Treponema pallidum in the skin during early syphilis represent the preliminary steps preceding dissemination to other organs. Immunohistochemistry directed to T. pallidum is a convenient means for reaching the diagnosis and for exploring the dissemination process. The present case illustrates the dermal clustering and the vascular spread of T. pallidum in a woman with acquired immu­no deficiency syndrome.