LAUSR

Syphilis is caused by the anaerobic filamentous spirochete, Treponema pallidum. Humans are the only known vectors. Transmission is predominantly vertical (congenital syphilis) or sexual (acquired syphilis), although indirect transmission may occur through contaminated objects such as tattoo needles or via blood transfusion. Oral manifestations are uncommon and may represent a diagnostic challenge because of its wide spectrum of clinical appearances. A 36-year-old man was referred for diagnosis of an oral ulcer ongoing for approximately 1 month. He had received a negative Venereal Diseases Research Laboratory (VDRL) test result 15 days earlier. On extraoral examination, no changes were observed. Intraoral examination revealed a single, painless ulcer, partially covered by a thin fibrin