Abstract: Two patients with primary syphilis were reported and relevant literatures are reviewed. Case 1 was a 34-year-old male who presented with patch and vesicle lesions on his penis for 10 days. Case 2 was a 55-year-old male who presented with ulcer lesions on his penis for 2 days. The toluidine red unheated serum test (TRUST) and treponema pallidum particle agglutination test (TPPA) test of case 1 were positive but both were negative for case 2. Polymerase chain reactions of Treponema pallidum (TP-PCR) in penile lesion secretions were positive for both patients. The diagnosis of primary syphilis was made.

Key words: primary syphilis, atypical