An Unusual Case of Rectal Mass Investigation Leading to Diagnosis of Syphilitic Proctitis

Document Type

Conference Proceeding

Publication Date

10-1-2024

Publication Title

Am J Gastroenterol

Abstract

Introduction: We present an unusual case of a patient with syphilitic proctitis presenting as severe constipation and hematochezia. Case Description/Methods: A wonderful 42-year-old man with a history of well controlled human immunodeficiency virus (HIV), prior small bowel resection and right hemicolectomy due to a gunshot wound, presents to the emergency department for evaluation of severe constipation and rectal bleeding over the past 8 days. Computed tomography of the abdomen and pelvis notes marked circumferential wall thickening in the rectum suspicious for rectal adenocarcinoma. Additionally, multiple enlarged mesorectal, superior rectal, and inferior mesenteric artery lymph nodes are suspicious for metastatic disease. The patient undergoes colonoscopy, which reveals a 9 cm partially obstructing fungating mass in the distal rectum suspicious for malignancy. The lesion is biopsied and evaluation scheduled with colorectal surgery and oncology. Final pathology reveals rectal mucosa with ulceration and acute and chronic inflammation with dense plasmocytic infiltrates. Treponema pallidum immunostaining highlights numerous organisms. The findings are diagnostic for active syphilis infection, and there is no evidence of cancer cells. Plans are made for outpatient infectious disease evaluation, but the patient does not follow up. The patient returns with recurrent dyschezia and 2.8 cm perirectal abscess for which he is treated with penicillin G for 3 weeks. Discussion: Syphilitic proctitis is a rare manifestation of syphilis that usually presents as proctitis, ulcer, and neoplasm, but lacks defining characteristics. This poses a diagnostic challenge as it mimics rectal cancer clinically, radiologically, and endoscopically. Patients with syphilitic proctitis typically present with obstructive bowel symptoms. Histologic sections are often required for diagnosis, and reveal prominent plasma cells and abundant Treponema pallidum. Several cases of syphilitic proctitis have been described in patients who are positive for HIV, indicating that this population may be at risk for this condition, even when well controlled.

Volume

119

Issue

10

First Page

S1903

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