P1265 - Syphilitic Proctitis: A Rectal Cancer Mimic

Devanshi Kajal, MD, Karissa Lambert, MD, Ahmed Hamed, MD, Hossein Movahed, MD
East Carolina University, Greenville, NC

Introduction: Syphilitic proctitis is a rare manifestation of syphilis. The clinical presentation coupled with non-specific endoscopic and histologic findings can make it difficult to distinguish from other etiologies of proctitis or malignancy. We report a case of syphilitic proctitis, which was radiographically suspicious for malignancy in a 38 year old male with human immunodeficiency virus (HIV) infection.

Case Description/Methods: A 38 year old Caucasian male with a past medical history of controlled HIV presented with a two week history of constipation and left lower quadrant abdominal pain. He denied hematochezia or bright red blood per rectum. He reported a history of unprotected anal intercourse. He denied a colonoscopy and family history of colorectal cancer. His initial labs demonstrated a white blood cell count of 4.24 k/uL, hemoglobin of 11.6 g/dL, CD4 count of 643, HIV viral load of 2880 copies/mL. Computed tomography of abdomen/pelvis demonstrated an abnormal mass-like enhancement in the rectum concerning for a rectal neoplasm. Carcinoembryonic antigen was normal. Flexible sigmoidoscopy revealed a moderate stenosis in the rectum with moderately congested mucosa and a few small, dispersed ulcers. Biopsies were taken and histopathology revealed marked active proctitis without malignancy. Cytomegalovirus and Herpes simplex virus were not identified. Rectal Neisseria gonorrhoeae and Chlamydia trachomatis nucleic acid amplification testing were negative. Subsequently, warthin-starry and spirochete immunohistochemistry stainings (Treponema pallidum) were performed on rectal biopsies which were positive. Syphilis antibodies were also positive with a reactive rapid plasma reagin titer of 1:2 with a prior nonreactive test. The patient was subsequently treated with benzathine penicillin 2.4 million units intramuscularly with clinical improvement.

Discussion: Syphilitic proctitis is rarely reported but is being more often recognized. The similar radiographic and endoscopic findings with those of other infectious proctitis and inflammatory bowel disease, as well as with malignancy can make the diagnosis difficult, which may lead to delayed or inappropriate treatment. This case highlights the importance of considering syphilitic proctitis in the differential diagnosis of rectal pathology, especially in high-risk populations.


Disclosures:


Devanshi Kajal, MD, Karissa Lambert, MD, Ahmed Hamed, MD, Hossein Movahed, MD. P1265 - Syphilitic Proctitis: A Rectal Cancer Mimic, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.