Primary syphilitic proctitis associated with human immunodeficiency virus infection in a male patient who had sex with men: a case report

Abstract

Background: Men who have sex with men (MSM) have frequent rectal infections. Although a large increase in incidence of syphilis has been reported in recent years, rectal chancre is a rare manifestation that can easily be neglected. Methods: We describe a male patient who had sex with men and presented with protracted chronic proctitis and scaly rashes. A diagnosis of HIV infection and early syphilis with syphilitic proctitis (rectal chancre) was confirmed by the findings of ulcerative proctitis under colonoscopy, the presence of Treponema pallidum in rectal ulcer biopsy specimens by immunohistochemistry, and positive serologic test results for human immunodeficiency virus type 1 (HIV-1) and syphilis. Results: Intramuscular benzathine penicillin G (2.4 million Units) given once a week for three consecutive weeks resulted in complete resolution of rectal and skin lesions. The patient also began regular anti-viral therapy against HIV infection. Conclusion: Immunohistochemical detection of Treponema pallidum in the primary infection tissue is a useful complement to serologic tests for the diagnosis of syphilis by clinical laboratories. Healthy and protective sexual behavior is advocated to avoid possible infections in MSM.