REV ARGENT COLOPROCT | 2024 | VOL. 35, N
o
2 CASE REPORT
PRIMARY RECTAL SYPHILIS MIMICKING RECTAL TUMOR Chinelli J. et al..
Primary rectal syphilis mimicking rectal tumor
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Javier!Chinelli,!Gusta vo !R o dr íguez
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Corporación Médica de Canelones (COMECA). Canelones, Uruguay
ABSTRACT
Introduction: Syphilis is a sexually transmitted disease with a
raising incidence.
Case description: 18-year-old male with an inflammatory rectal
pseudo-tumor. After diagnosis, antibiotic therapy was administered
with uneventful recovery.
Discussion: Rectal syphilis is a rare condition, with particular
endoscopic and imaging findings that allow differentiation from
rectal malignancy. Direct visualization of Treponema pallidum with
immunohistochemistry staining confirms the diagnosis.
Conclusion: Syphilitic proctitis must be suspected among high-risk
patients with atypical rectal tumors. Active management of sexual
partners is crucial for early diagnosis and treatment.
Key words: syphilis, proctitis, pseudo-tumor
INTRODUCTION
Syphilis is an infectious disease caused by the bacteria
Treponema pallidum (spirochete) and is transmitted by
direct contact. Its incidence has increased up to 3 times in
recent years, particularly in men who have sex with men,
whether or not they are carriers of the human immunodefi-
ciency virus (HIV), although the association between both
pathologies is very frequent, up to a 30-40%.
1
We report a case of primary rectal syphilis (syphilitic procti-
tis), a rare occurrence of the disease, particularly in its
pseudotumoral presentation.
CASE
An 18-year-old male patient, with multiple sexual partners
and unprotected anoreceptive intercourse, with no other
relevant clinical history, consulted for proctalgia, rectal
bleeding, and tenesmus of 2-week duration. The proctologi-
cal examination highlights the absence of perianal lesions
and the digital rectal examination reveals immediately above
the rectal ring a circumferential tumor that bleeds easily,
firm, not very mobile, somewhat painful, whose proximal
edge cannot be reached.
Colonoscopy shows a circumferential thickening of the
rectal wall up to 10 cm from the anal verge, with soft muco-
sa, distensible to insufflation, intensely congestive with
some superficial ulcerations covered with fibrin (Fig. 1A),
mamelonated near the anal canal (Fig. 1B).
Magnetic resonance imaging (MRI) of the pelvis shows
regular and uniform thickening of the rectal wall, hy-
pointense on T2, and multiple mesorectal nodes (Fig. 2).
HIV and VDRL tests were negative, while the endoscopic
biopsy showed the presence of spirochetes using an im-
munohistochemical technique (Fig. 3), confirming the
diagnosis of rectal syphilis.
Treatment was carried out by administering benzathine
penicillin G 2.4 million IU weekly for 3 weeks. There was a
good clinical response with resolution of symptoms and
complete remission of endoscopic lesions. Fig. 4 shows the
endoscopic appearance of the rectum after treatment.
Figure 1. Endoscopic appearance of the rectal lesion. A. Parietal thickening. B. Mamelonated mucosa.
Figure 2. MRI. A. Axial section. B. Sagittal section. Rectal
parietal thickening (white arrows) and mesorectal enlarged
lymph nodes (yellow arrows).
Figure 3. Immunohistochemistry. Spirochetes
are identified (arrows).
The authors declare no conflict of interest. Javier Chinelli: jchinelli01@gmail.com
Javier Chinelli https://orcid.org/0000-0003-2381-697X