1546. Update in Syphilis Proctitis: Insights from a Case Series and Literature Review

BACKGROUND: In the US, syphilis infections have increased 71% since 2014. Proctitis is a rare manifestation of early syphilis transmitted through anal intercourse. We suspect that its misdiagnosis results from physician under-awareness and thus we present the largest case analysis to date of syphilis proctitis. METHODS: We searched PubMed and Scopus for articles describing cases of proctitis in which Treponema pallidum was a likely causative pathogen based on serologies, and/or organism-specific staining of anorectal biopsy specimens. Furthermore, we conducted chart review to identify cases of syphilis proctitis diagnosed within our health center from 2011-2019. Pertinent data were extracted from the articles and medical records and analyzed to provide a summative account. RESULTS: 53 cases of syphilis proctitis were identified in 38 articles. 7 additional cases were diagnosed at our institution, totaling 60 cases. All cases of syphilis proctitis were described in individuals of male sex assignment at birth. The age at diagnosis ranged from 15 to 73 years (average 39 years). In 48 cases (92%) men endorsed sex with men. In 27 cases (56%) individuals were HIV co-infected. Syphilis proctitis presented most commonly with hematochezia (68%) and anal pain (48%). The most common physical exam findings were rectal mass (38%), lymphadenopathy (33%), and rash (31%). Non-treponemal titers averaged 1:60 (range 1:2-1:1024). Endoscopy was performed in 52 cases and most commonly showed anorectal mass (42%) and anorectal ulcer (35%). In 38 cases (68%), histopathology revealed a chronic lymphoplasmacytic inflammatory infiltrate, and in 14 of these cases (37%), prominent plasma cells were described. In 24 cases (77%), treponema immunohistochemical stain revealed spirochetes. CONCLUSION: Syphilitic proctitis should be suspected in boys and men presenting with lower gastrointestinal symptoms. Histopathology, while suggestive, is not pathognomonic, and serology and specific tissue staining are required to make the diagnosis. Given overlapping symptoms and histology with inflammatory bowel disease, the diagnosis may be delayed resulting in personal and public health consequences. A sexual history should be routinely elicited and further testing for syphilis pursued if exposure is suspected. DISCLOSURES: All Authors: No reported disclosures