Anal Canal Syphilis: A Challenging Diagnosis for the Gastrointestinal Pathologist
Purva Gopal, Robert M Genta, Rajal Shah. Miraca Life Sciences Research Institute, Irving, TX
Background: The incidence of syphilis has been increasing over the past few years. Its manifestations as a venereal disease are well described; in contrast, its presentation as primary anal canal disease remains relatively unexplored and gastrointestinal pathologists may rarely consider it in their differential diagnosis. In addition, the demonstration of serum antibodies has traditionally remained the mainstay for diagnosis. The aims of this study are to describe the clinical and histological aspects of anal syphilis and explore the diagnostic utility of T. pallidum IHC.
Design: From a series of 11,374 anal biopsies received between 2002-2012, after excluding cases of anal intraepithelial dysplasia/condyloma, neoplasms, and inflammatory bowel disease, we identified patients biopsied for evaluation of isolated anal ulcers. Clinical and histologic characteristics, and T. pallidum IHC stains were reviewed.
Results: Ten patients (9 men and 1 woman) met our inclusion criteria. In 5 cases syphilis was suspected and T. pallidum IHC was performed; 3 (all men) were positive. Histologic features included: ulcer with non-specific chronic inflammation; band-like chronic inflammatory infiltrates rich in plasma cells and rare poorly-formed granulomas. T. pallidum IHC highlighted numerous organisms in the epidermis, the dermo-epidermal junction and the papillary dermis. Syphilis was neither previously diagnosed nor suspected in any of these patients. Serologic testing, performed after T. pallidum was identified histologically, was positive in all 3 patients, one of whom was also HIV positive. One patient subsequently developed syphilitic encephalitis.
Conclusions: Syphilis can present as primary anal disease, especially in men with high-risk behaviors, but this clinical suspicion is rarely conveyed to the pathologist. Therefore, it should be suspected in biopsies from isolated anal ulcers, particularly in the presence of inflammatory infiltrates rich in plasma cells. T. pallidum IHC is a useful tool that may lead to an early diagnosis and help clinicians to properly manage these patients.
Wednesday, March 6, 2013 9:30 AM
Poster Session V # 103, Wednesday Morning