Late syphilis mimicking a pseudolymphoma of the skin.

After a period of declining incidence of syphilis in most of Western Europe until the late 1990s, reports about an increasing trend have been published recently. In contrast to the rising incidence of early syphilis, cases of late (tertiary) syphilis are rarely seen in developed countries. In this report, we describe a 54-year-old patient with infiltrated erythematous plaques on his forehead and neck that histologically revealed a dense lymphocytic cell infiltrate with numerous plasma cells. The serologic examination was characteristic of syphilis and in conjunction with the clinical presentation and the patient's history led to the diagnosis of tertiary syphilis. The diagnosis of this late stage of syphilis can be difficult as clinical pictures can be misleading. Peculiar skin lesions should always remind clinicians of this infectious disease which has still to be considered in differential diagnoses in dermatology.