Abstract

Background : Syphilis (“the great imitator”) can present with range of clinical and histopathologic appearances, with variable presentation and false-negative laboratory tests in HIV-positive patients. Case presentation :A 39-year-old male with HIV (viral load 0, CD4 count 1028) and prior treated secondary syphilis presented with a pruritic rash on the back, flank, and lower abdomen. Examination revealed erythematous, finely scaly patches, with a clinical differential diagnosis including fungal infection, eczema, and secondary syphilis. Histopathologic features were minimal, with very mild perivascular inflammatory infiltrate. Typical “spaghetti and meatballs” PAS positive organisms of tinea versicolor were seen. Given the history, an anti-spirochete antibody immunohistochemical study was performed and showed rare organisms in the epidermis. RPR was also positive. A diagnosis of secondary syphilis with associated tinea versicolor was made. Discussion :We describe an unusual case of secondary syphilis with associated tinea versicolor and very subtle/minimal microscopic findings in an HIV-positive patient. Secondary syphilis shows a spectrum of histologic findings. Misdiagnosis is possible when few histologic findings are present. HIV-positive patients with primary/secondary syphilis may have high IL-10 and consequently reduced inflammation. Conclusions :Despite minimal inflammation and concurrent tinea versicolor, the history prompted evaluation for secondary syphilis. This case illustrates the importance of clinicopathologic correlation and a collaborative partnership between dermatopathology and dermatology in order to prevent a serious misdiagnosis with the potential for adverse clinical outcomes.

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