Abstract

Syphilis is sexually transmitted infectious disease caused by treponema pallidum. Due to the global rising incidence of syphilis infection, it is essential to recognize the various clinical and histological manifestation of this emerging disease. The occurrence of granulomatous inflammatory reaction in secondary syphilis is unusual and may be confused with other granulomatous dermatoses, hence known as "great imitator". We present two cases of secondary syphilis that presented initially as non-tender, non-pruritic diffuse indurated erythematous papules and plaques on the upper extremities and torso for eight weeks. Both cases were missed in the initial presentation and worsened upon in-appropriate treatment with topical triamcinolone. The differential diagnosis based on the clinical and histopathological findings was broad. After detailed microscopic examination and serological testing for secondary syphilis, the diagnosis was established. Both patients tested negative for HIV and were immunocompetent. No history of medications intake was noted. Microscopically, both cases demonstrated extensive non-caseating granulomas within the dermis along with a robust lymph histiocytic infiltrate admixed with plasma cells. Special stains (PAS, GMS, AFB and Fite stain) were negative for fungal and bacterial organisms. Warthin Starry stain was negative in both cases. Clinicopathological correlation was recommended. The treponemal immunohistochemical stain highlighted numerous spirochetes. Serological testing was essential in confirming the diagnosis. Penicillin treatment initiated complete resolution of symptoms in both cases. It is crucial to recognize various histological variability of secondary syphilis that can mimic other diseases entities. Granulomatous dermatitis in secondary syphilis should be kept into consideration when examining skin specimens of high-risk patients to guide appropriate treatment and prevent the development of disease to advanced stages.

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