Syphilitic Proctitis

A 50-year-old man presented with painful hematochezia one month after condomless receptive anal intercourse. Serologic testing confirmed syphilis with a positive Treponema pallidum particle agglutination assay and an RPR titer of 1:32; HIV, chlamydia, and gonorrhea tests were negative. Colonoscopy revealed a 3-cm ulcer in the distal rectum. Biopsy showed histiocytes and lymphoplasmacytic infiltrates, with numerous spirochetes identified via immunohistochemical staining. The diagnosis of syphilitic proctitis was confirmed. Following benzylpenicillin treatment, symptoms resolved, with repeat RPR titer dropping to 1:8 and colonoscopy showing ulcer healing.

A 50-year-old man presented with painful hematochezia one month after condomless receptive anal intercourse. Serologic testing confirmed syphilis with a positive Treponema pallidum particle agglutination assay and an RPR titer of 1:32; HIV, chlamydia, and gonorrhea tests were negative. Colonoscopy revealed a 3-cm ulcer in the distal rectum. Biopsy showed histiocytes and lymphoplasmacytic infiltrates, with numerous spirochetes identified via immunohistochemical staining. The diagnosis of syphilitic proctitis was confirmed. Following benzylpenicillin treatment, symptoms resolved, with repeat RPR titer dropping to 1:8 and colonoscopy showing ulcer healing.