HIV-positive man with ulceronecrotic skin lesions.

Diagnosis: malignant syphilis and coinfection with human immunodeficiency virus (HIV). A skin biopsy was performed, and the diagnosis of syphilis was suggested by the histopathological findings (figure 1). Titers of Treponema pallidum were 11:64 on hemagglutination assay, and a fluorescent treponemal antibody absorption test had positive results. After treatment with intravenous penicillin G (18 million U per day), complete resolution of the skin lesions was observed, confirming the diagnosis of syphilis. Malignant syphilis (lues maligna) is a rare manifestation of secondary syphilis. However, since the onset of the HIV infection epidemic, there have been more reports of the disease, suggesting that patients with HIV infection may be at increased risk of developing the disease [1, 2]. In patients with HIV infection who present with ulceronodular skin lesions, malignant syphilis should always be considered, although skin biopsy samples rarely show syphilis spirochete, which makes the diagnosis more challenging [3]. Acknowledgments Potential conflicts of interest. N.Y. and A.I.: no conflicts.