A 39-year-old woman presented with a 6-week history of an ulcerated and indurated lesion in the upper lip (Fig. 1). The histological study showed an ulcer with dense lymphoplasmacytic infiltrate and the immunohistochemistry (IHC) was positive for spirochetes. Both, the rapid plasma reagin test (RPR) and the microhemaglutination of the Treponema pallidum (MHA-TP) test were reactive with a RPR of 1:32.
Due to physical examination, biopsy, IHC and laboratory tests (MHA-TP and RPR) the patient was diagnosed with primary syphilis. Infective syphilis is caused by T. pallidum, an anaerobic filamentous spirochete.1 The primary stage is known as syphilis chancre.2 The mouth is a rare place of presentation of syphilis chancre, with 10–20% of cases intrarectal, perianal or oral lesions.2 The treatment of primary syphilis is intramuscular benzathine penicillin.3 The patient and his partner were treated with 2,400,000, intramuscular benzathine penicillin with a complete resolution of the lesion (Fig. 2).
Conflicts of interest
The authors declare no conflicts of interest.
