Rectal syphilis mimicking rectal cancer.

Rectal syphilis, known as a great masquerader, can be difficult to diagnose because of its variable symptoms. Gastroenterologists should be aware of the possibility of rectal syphilis when confronted with anorectal ulcers, and should gather a detailed history about sexual preferences and practices, including homosexuality. We report a case of primary rectal syphilis mimicking rectal cancer on radiologic imaging. In this report, we described the clinical, endoscopic, and radiologic features of this rare case.