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Secondary syphilis as a single annular plaque on the penis mimicking granuloma annulare
How to cite this article: Guillén BF, von der Weth MM, Oñate CV, Tapial JM, Bel PH. Secondary syphilis as a single annular plaque on the penis mimicking granuloma annulare. Indian J Dermatol Venereol Leprol 2021;87:438.
A 44-year-old homosexual man currently on antiretroviral therapy for HIV infection presented with a three month history of a single annular red plaque of two cm diameter with central clearing and raised borders on the penis, associated with mild pruritus [Figure 1]. There were no lesions in the oral cavity, palms, or soles. Lymphadenopathy and systemic symptoms were absent.
Histopathological examination revealed a dense dermal infiltrate composed of lymphocytes and plasma cells in a lichenoid pattern with epitheliotropism. Immunohistochemistry showed the presence of Treponema pallidum. Rapid plasma reagin (RPR) test was reactive in 1:32 dilution and fluorescent treponemal antibody absorption test was positive. The CD4 lymphocyte count was within normal limits. A diagnosis of secondary syphilis was made and the patient received 2.4 million units of penicillin G benzathine weekly for 3 weeks, despite the existing guidelines preferring a single-dose therapy, leading to a complete healing of the lesion. Serology performed 3 months after treatment showed an improved RPR of 1:4 dilution.
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The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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