Primary syphilis of the oropharynx: an unusual location of a chancre

A 33-year-old man presented with a two-week history of an asymptomatic ulcer of the oropharynx and submandibular lymph nodes swelling. Laboratory examinations were normal, but serological tests revealed positivity for rapid plasma reagin, Treponema pallidum haemagglutination assay and anti-T. pallidum IgM antibodies. Since the patient denied any homosexual relationship, a biopsy of the lesion was performed, which confirmed primary syphilis. The patient received an intramuscular injection of Benzathine Penicillin G (2.4 MU) with complete resolution of the lesion. Extragenital chancres occur in at least 5% of patients with primary syphilis, and the oral mucosa is the most frequent location as a consequence of orogenital/oroanal contact with an infectious lesion. Because of their transient nature, these oral ulcerations are often underestimated by the patient or by any unsuspecting clinician. Health professionals should consider the recent sexual history of their patients and should be prepared to recognise oral and systemic manifestations of sexually transmitted infections.