Syphilitic proctitis

Abstract

Syphilitic proctitis is a rare disease that usually presents as proctitis, ulcer, and neoplasm but lacks pathognomonic clinical symptoms. It is thus difficult to diagnose and may be treated inappropriately. We report a 31-year-old man who had a hard, ulcerated mass that occupied the rectal and sigmoid colon wall and mimicked a tumor. Fortunately, a biopsy of the mass demonstrated Treponema pallidum organisms consistent with syphilitic proctitis. The patient was successfully treated with intravenous benzyl penicillin, resulting in improvement in his proctitis.

Syphilitic proctitis is a rare disease that usually presents as proctitis, ulcer, or a mass lesion without pathognomonic clinical symptoms. It is therefore difficult to diagnose and may occasionally be treated inappropriately. We report a case of syphilitic proctitis that presented as a rectal mass.

CASE REPORT

A 31-year-old man presented to the hospital with an 11-month history of rectal bleeding, tenesmus, a 20-pound weight loss, mucoid rectal discharge, and blurry vision. He had had receptive anal intercourse with multiple homosexual men. Rectal examination revealed a tender fungating mass protruding from the anal verge (Figure 1). The antibody for human immunodeficiency virus was positive, and the CD4 cell count was 240 cell/mL. Computed tomography (CT) of the abdomen and pelvis showed circumferential thickening of the rectum extending to the anal verge and multiple enlarged perirectal lymph nodes. Colonoscopy showed an irregular rectal mass segment and hyperemia and erosions involving the rectum and distal sigmoid colon.

Figure 1.

A fungating rectal mass protruding from the anal verge.

The rectal mass was biopsied. Histological findings of the biopsy showed fragments of polypoid granulation tissue with prominent plasma cells on hematoxylin and eosin stain (Figure 2a) and abundant Treponema pallidum organisms on immunohistochemical staining consistent with syphilitic proctitis (Figure 2b). Rapid plasma reagin and Treponema antibody were positive. He underwent lumbar puncture and was confirmed to have neurosyphilis. The patient was treated for 3 weeks with intravenous benzyl penicillin, resulting in resolution of his visual complaints and improvement in the proctitis based on endoscopy. The endoscopy also revealed that the rectal mass had resolved (Figure 3).

Figure 2.

Rectal mass biopsy showing (a) polypoid granulation tissue with prominent plasma cells and (b) abundant T. pallidum organisms as highlighted by immunohistochemical study.

Figure 3.

The fungating rectal mass resolved endoscopically after treatment with benzathine penicillin G.

DISCUSSION

There has been a reemergence of syphilis with a global increase in the incidence of sexually transmitted infections (1). Syphilitic proctitis is a rare complication, with most cases seen in patients who practice receptive anal intercourse. From 2005 to 2013, the Centers for Disease Control and Prevention estimated that the number of primary and secondary syphilis cases reported had almost doubled from 8,724 to 16,663. (2).

Syphilitic proctitis varies in presentation, including chancres in primary syphilis that spontaneously heal, mass-like lesions as seen in our patient, and ulcers (3). These features often overlap with inflammatory bowel disease, other infectious causes, and nonsteroidal antiinflammatory drug enteropathy. CT and colonoscopy findings typically show features overlapping with malignancies and nonspecific inflammatory changes. None of these findings confirm the diagnosis of syphilitic proctitis. Therefore, high clinical suspicion is imperative for expedient diagnosis. Tissue biopsy with staining for T. pallidum (though not always present) and infectious laboratory evaluations helped in reaching the correct diagnosis. First-line treatment is benzathine penicillin G.