S2191 A Case Report of Syphilitic Proctitis Mimicking Rectal Cancer

Abstract

Introduction: Syphilis rarely affects the gastrointestinal tract, and even more rarely manifests with lower gastrointestinal signs and symptoms. We report a rare case of syphilitic proctitis that presented with inguinal lymphadenopathy and pain with defecation mimicking anorectal malignancy. Case Description/Methods: A 31-year-old male with a history of multiple, recent male sexual partners, sexually transmitted infections (STIs), anxiety, depression, and migraines presented to the emergency department with a 2-month history of left inguinal pain, perianal pain, and pain with defecation. His initial exam was notable for a palpable rectal mass and tender left inguinal lymphadenopathy. CT abdomen/pelvis demonstrated a markedly enlarged left inguinal lymph node measuring 3.9 x 2.7 x 3.1 cm with multiple enlarged perirectal and left internal iliac lymph nodes, radiographically concerning for metastatic disease. Colonoscopy revealed congested mucosa in the rectum and a palpable external rectal mass on digital rectal exam. He was tested for sexually transmitted diseases and was found to have a reactive RPR with a titer of 1:128 and positive T. pallidum antibodies. His biopsy resulted with findings of syphilitic proctitis and spirochetosis confirmed by treponema pallidum immunostain, consistent with secondary syphilis. He was treated with a 14-day course of doxycycline (due to penicillin allergy) with initial improvement in symptoms. Discussion: Syphilis is an important public health issue with increasing cases in the United States over the last 20 years. Syphilis uncommonly affects the gastrointestinal tract, and even less commonly the lower GI tract. Syphilitic proctitis most often presents with pain on defecation, rectal bleeding, tenesmus, and diarrhea and is often difficult to distinguish from inflammatory bowel disease or malignancy. Given the rise in sexually transmitted infections, it is important for providers to be aware of this presentation, which requires a thorough sexual history and prompt testing if exposure is suspected, to prevent ongoing transmission and development of complications. Our case highlights the rare presentation of syphilis and the importance of screening for STIs in high-risk patients.