Syphilis incidence has exponentially increased in recent decades worldwide,1 particularly, although not exclusively, among men who have sex with men. The primary stage of syphilis is defined by a chancre at the site of the first contact, which is usually the anogenital area. The chancre is typically a single, painless, pink/red round ulcer with well-defined and indurated borders, varying in size from 0.3 to 3 cm, and with a smooth base sometimes covered by serous exudate. Spontaneous healing occurs within 3–4 weeks without scar.1 Regional lymphadenopathy occurs in up to 80% of cases. Atypical chancres vary in localisation, morphology and associated symptoms.1

We describe two cases of atypical primary syphilis in two immunocompetent individuals. We defined the chancres as ‘phagedenic’ because they were characterised by extensive local tissue destruction and superinfection.

Case 1. A previously healthy 54-year-old man presented with a 20-day history of a slightly painful penile lesion that appeared 1 month after unprotected sexual intercourse. Examination revealed a large oval, infiltrated erythematous plaque at the ventral surface of the shaft, 3×3 cm in diameter, …