Solitary syphilitic chancre affecting (a) male and (b) female external genitalia. Solitary syphilitic chancre affecting (a) male and (b) female external genitalia. A chancre is the archetypal feature of primary syphilis. These ulcers are classically anogenital, solitary, indurated and painless; however, in atypical cases they may be multiple and painful, and can occur at extra-anogenital sites. Chris A Lamb et al. Frontline Gastroenterol 2013;4:32-40 Copyright © BMJ Publishing Group Ltd & British Society of Gastroenterology. All rights reserved.