Classically known as the "Great Imitator", the diagnosis of syphilis continues to be an enormous challenge. We describe a case of isolated oral lesions as the sole presentation of secondary syphilis and only clinical clue to previously undiagnosed human immunodeficiency virus infection. The current increase in new cases of syphilis is leading to reemergence of forgotten old scenarios, which physicians should bear in mind within the differential diagnosis of their daily practice.