RESUMO
Primary syphilic chancre most often involved genitalia, with 12% to 14% extragenital lesions. This article describes a rare case of a female patient with labial ulcer and diagnosed as oral syphilis (OS), an uncommon presentation of primary syphilis. OS is transmitted through orogenital contact.This study is case report and literature review.We report a 27-year-old woman with painless, ulcerative, and indurated lesion on her lower lip and a 7-day history of symmetrically distributed nonpruritic macules. OS was diagnosed based on clinical presentations and serologic test and patient's oral ulcer was cured with intramuscular penicillin G benzathine. However, both the patient and her husband denied any orogenital sexual history before. In addition, her husband was also diagnosed as syphilis later in our clinic. He reported having orogenital contact with other people.Therefore, this is a rare case of OS transmitted through kissing.