[635] Sexually Transmitted Disease (STD) Proctitis: Clues to a Frequently Missed Diagnosis

Christina A Arnold, Elizabeth Montgomery, Lysandra Voltaggio. Johns Hopkins, Baltimore; George Washington, Washington, DC

Background: Recent European outbreaks of lymphogranuloma venereum (LGV) and the rising incidence of syphilis underscore the importance of recognizing these STDs, especially in HIV+ men who have sex with men (MSM). LGV and syphilis can present as isolated proctitis, providing an important diagnostic opportunity. We report a distinctive pattern of mononuclear inflammation, crypt distortion, and fibrosis in patients with STD proctitis.
Design: The syphilis proctitis group consisted of cases prospectively identified by a distinctive inflammatory pattern in patients later shown to be RPR+. LGV proctitis cases were retrieved from patients from an STD clinic known to have LGV proctitis who had undergone anorectal biopsies.
Results: We identified 12 cases from 10 patients whose anorectal biopsies showed STD-associated features. All patients were HIV+ men (average CD4 count 472/mm3). All 6 with an available sexual history were MSM; 3 had documented receptive anal intercourse. The majority presented with rectal bleeding (8/10) and pain (7/10). Endoscopic impressions included rectal nodularity (10/12) and ulcerations (7/12). Three cases were previously misdiagnosed (3/10) as ulcerative colitis, mucosal prolapse, or nondiagnostic.
The syphilitic proctitis study group consisted of 10 colonic biopsies from 8 patients. The RPR titer ranged from 1:2 to 1:1024 (median 1:20). The majority of the biopsies had prominent plasma cell-rich mononuclear inflammation, perivascular plasma cells, crypt distortion, and fibrosis (8/10). Additional findings included ulcers (5/10) and poorly formed granulomas (2/10). The majority of cases containing squamous mucosa showed a plasma-cell rich, lichenoid pattern of chronic inflammation, perivascular plasma cells (3/4), and ulcers (3/4).
The LGV study group consisted of 2 colonic biopsies from 2 patients. Biopsies showed prominent chronic inflammation (including plasma cells) and fibrosis (2/2).
Conclusions: We report a unique histologic pattern associated with STD proctitis: prominent mononuclear infiltrates associated with crypt distortion, fibrosis, and lacking significant acute inflammation, features potentially mimicking IBD. Moreover, the histologic findings of STD proctitis differ slightly from the classic features described in the skin: plasma cells and perivascular lymphoplasmacytic infiltrates were less prominent in syphilis proctitis than that typically seen with cutaneous syphilis. This unique pattern is important to recognize, especially in MSM, to suggest additional testing for STD proctitis and to avoid the potential pitfall of misdiagnosing IBD.
Category: Gastrointestinal

Monday, March 19, 2012 11:15 AM

Platform Session: Section D, Monday Morning


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