A nonspecific ulcer on upper lip presented as the first and sole sign of syphilis.

Syphilis, a sexually transmitted disease, can be categorized as acquired syphilis and congenital syphilis, manifesting diverse lesions involving multiple sites. Oral manifestations at the primary stage of acquired syphilis are usually characterized by its short period and non-specific varied presentations. And oral ulcers as initial and the only presentation of syphilis oral lesions are infrequent and occur in less than 2% of patients. Because of its transient nature and variable manifestations which could mimic other oral ulcerative lesions, oral syphilis presenting as sole ulceration at early stage can be easily neglected and rather difficult to diagnose. Herein, we report a 35-year-old female patient manifested a sole atypical ulceration on her upper lip for approximately 1 month. We highlighted the importance of early and accurate diagnosis, focused on the characteristics of oral chancre, and gave an insight to the differential diagnoses, which would be enlightening and useful in clinical practice.