Lymphogranuloma venereum proctosigmoiditis is a mimicker of inflammatory bowel disease.

There has been an increasing prevalence of lymphogranuloma venereum (LGV) or Chlamydia trachomatis (C. trachomatis) cases among the men who have sex with men (MSM) population, particularly in Europe and North America. These cases may present with an incomplete or undisclosed history and proctosigmoiditis without characteristic adenopathy syndrome. During the initial evaluation and colonoscopy, there is a strong clinical and endoscopic suspicion of inflammatory bowel disease (IBD) by virtue of presentation and endoscopic and histological findings. The diagnosis of IBD is subsequently modified to LGV proctosigmoiditis when one or more of the following transpire: (1) there is failure of response to IBD therapy; (2) additional components of history (MSM/travel) may be identified; (3) return of initially performed Chlamydia antibody test is positive; and (4) response to antibiotics effective against Chlamydia. We describe three such cases initially suspected to be an inflammatory bowel disease and subsequently identified as C. trachomatis proctosigmoiditis.