Authors
Raul Marquez, MS3 (Kirk Kerkorian School of Medicine at UNLV) Taha Shaikh, MD (Kirk Kerkorian School of Medicine at UNLV) Badrunissa Hanif, MD (Kirk Kerkorian School of Medicine at UNLV)
Introduction
Syphilis, a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum, has earned the moniker “the great imitator” due to its ability to mimic various diseases - making its diagnosis challenging. Successful diagnosis and staging of syphilis requires a comprehensive evaluation of the patient's clinical, pathological, and social history. This case report highlights the complexity of syphilis diagnosis and the importance of maintaining a high index of suspicion, particularly in cases with unusual clinical presentations and inconclusive histopathological results.
Case Presentation
A 58-year-old male without significant past medical history presented with a painless skin lesion in the right temporal region measuring 6 cm x 4 cm. The lesion displayed central necrosis, purulence, and surrounding erythema that worsened over the course of a week. Additionally, the patient reported experiencing painless penile ulcers that had spontaneously resolved a few weeks before admission, an ulcerative lesion on the lateral aspect of his tongue, and diffuse painless lymphadenopathy. The patient also presented with a 6 cm x 12 cm left-sided mobile, round, and firm subcutaneous abdominal mass. The diagnostic workup included a positive Reactive Fluorescent Treponemal Antibody (FTR), a significantly elevated Rapid Plasma Reagin (RPR) of 1:256, and a negative HIV serology. Surprisingly, the histochemical staining for Treponema pallidum from the temporal lesion was negative. The patient's white blood cell count (WBC) was elevated at 12.19K/mm3, erythrocyte sedimentation rate (ESR) of 74 mm/hr, and a C-reactive protein (CRP) level of 15 mg/L. A wound culture of the temporal lesion yielded Methicillin-resistant Staphylococcus aureus (MRSA) growth. The patient received 24 million units of intravenous penicillin G per day for two weeks, followed by a 28-day course of oral doxycycline to treat syphilitic symptoms and a 10-day course of Linezolid for the superimposed MRSA bacterial infection. Following the initiation of intravenous penicillin G therapy, there was a rapid reduction in the size of the cutaneous lesion in the temporal region, and the abdominal mass showed signs of shrinkage.
Discussion
The clinical presentation of this case is unique due to the severe soft-tissue lesion erupting in an immunocompetent patient, highlighting the diverse clinical manifestations of syphilis; including advanced or latent forms, e.g., secondary and tertiary syphilis. A crucial diagnostic aspect of this case was the inconclusive histochemical staining for Treponema pallidum. However, other clinical and laboratory findings provided support for a diagnosis of syphilis including the timeline of varying cutaneous lesions, high RPR titers, and a positive response of symptoms to intravenous penicillin G therapy. Histochemical staining has a reported sensitivity of approximately 70%; therefore, a negative result, as seen in this case, cannot independently rule out a syphilis infection. This potential barrier to exclusively relying on histopathological evidence further emphasizes the importance of evaluating for other supportive clinical and serological evidence when confronted with a suspicious syphilis infection. This case hopes to re-initiate the awareness physicians and other clinicians should carry on the diverse clinical manifestations of syphilis and the necessity of maintaining a high index of suspicion in cases with unusual presentations.
References
- Tudor ME, Al Aboud AM, Leslie SW, et al. Syphilis. StatPearls Publishing; updated 30 May 2023.
- Pleimes M, Hartschuh W, Kutzner H, et al. Malignant syphilis with ocular involvement and organism-depleted lesions. Clin Infect Dis. 2009;48:83-85. [PMID: 19035775] doi:10.1086/594127
- Flamm A, Parikh K, Xie Q, et al. Histologic features of secondary syphilis: a multicenter retrospective review. J Am Acad Dermatol. 2015;73:1025-1030. [PMID: 26464219] doi:10.1016/j.jaad.2015.08.062
- Balagula Y, Mattei PL, Wisco OJ, et al. The great imitator revisited: the spectrum of atypical cutaneous manifestations of secondary syphilis. Int J Dermatol. 2014;53:1434-1441. [PMID: 25312512] doi:10.1111/ijd.12518
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