Syphilitic proctitis presenting as locally advanced rectal cancer: A case report

Introduction: Syphilis is an infectious disease that is uncommonly encountered in surgical patients. We present a case of severe syphilitic proctitis leading to large bowel obstruction with imaging findings mimicking locally advanced rectal cancer.Presentation of case: A 38-year-old man who had sex with men presented to the emergency department with a 2 week history of obstipation. The patient's medical history was significant for poorly controlled HIV. Imaging demonstrated a large mass in the rectum and the patient was admitted to the colorectal surgery service for management of presumed rectal cancer. Sigmoidoscopy demonstrated a rectal stricture and biopsies showed severe proctitis without evidence for malignancy. Given the patient's history and discordant clinical findings an infectious workup was pursued. The patient tested positive for syphilis and was diagnosed with syphilitic proctitis. He underwent treatment with penicillin and although he experienced a Jarisch-Herxheimer reaction, his bowel obstruction completely resolved. Final pathology on the rectal biopsies demonstrated positive WarthinStarry and spirochete immunohistochemical stain.Discussion: This case illustrates key aspects in the care of a patient with syphilitic proctitis mimicking an obstructing rectal cancer, including the need for high clinical suspicion, thorough evaluation including sexual and sexually transmitted disease history, multidisciplinary communication, and management of the JarischHerxheimer reaction.Conclusion: Severe proctitis leading to large bowel obstruction is a possible presentation of syphilis, and a high degree of clinical suspicion is necessary to be able to accurately identify the cause. An increased awareness of the Jarisch-Herxheimer reaction following treatment of syphilis is critical to provide appropriate care in this patient population.