12th May 2024

A 28-year-old woman presents to the clinic with a painless ulcer on her external genitalia.

A 28-year-old woman presents to the clinic with a painless ulcer on her external genitalia. She reports having unprotected sexual intercourse a month ago during her vacation. On examination, the ulcer is round, clean, with a firm border, and there is non-tender enlargement of the inguinal lymph nodes. There are no other skin lesions noted.

Which of the following is the most likely diagnosis?