29th April 2024

A 30-year-old man presents with a painless ulcer on his genitalia.

A 30-year-old man presents with a painless ulcer on his genitalia. He first noticed the ulcer three weeks ago, and it has not increased in size or caused any discomfort. On examination, the ulcer is round, with a clean base and well-defined borders. There are no signs of discharge, and the inguinal lymph nodes are non-tender and slightly enlarged.

Which is the most likely diagnosis?