Non typical syphilis: Presentation of a case

Syphilis is a sexually transmitted disease that should be considered in the differential diagnosis of cutaneous lesions in HIV patients. We report the case of a patient who presented to the dermatology clinic with an erythematous plaque, appearing to be a cutaneous lymphoma, mycobacteria infection, histoplasmosis or esporotricosis. The real diagnosis of secondary syphilis was delayed because of a prozone phenomenon. The clinical findings, epidemiology and histologic findings establish the diagnosis of atypical secondary syphilis.