Syphilis as an atypical cause of perianal fissure

We present the case of a 29-year-old woman who attended a surgical outpatient clinic with symptoms of perianal fissure due to syphilitic infection. This uncommon aetiology of a common condition is often alluded to in textbooks, but little information exists in the scientific literature regarding the pathogenesis, presentation and treatment of fissure-in-ano secondary to syphilis. We present the case and an overview of the topic aimed at surgeons and clinicians who manage patients with perianal pathology. Syphilis is far from a disease of antiquity; in patients presenting with fissure-in-ano a thorough sexual history and sexually transmissible infection screening in at-risk groups may avoid mis-diagnosis, community transmission and unnecessary procedures.