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Updated: May 28, 2026

Procedures for In Vitro Cultivation of Treponema pallidum, the Syphilis Spirochete
Published on: January 24, 2025
Pathologically confirmed malignant syphilis in an HIV-infected patient
Naoki Yanagisawa1, Minoru Ando, Akifumi Imamura
1Department of Infectious Diseases, Tokyo Metropolitan Komagome Hospital, Japan. naokiy97@gmail.com
Abstract:
We report a case of pathologically confirmed malignant syphilis in an HIV-infected patient. Physical examinations revealed ulceronecrotic skin lesions. Skin biopsies demonstrated syphilis spirochetes on immunohistochemical stain, and syphilis serological titers were positive. Treatment with intravenous penicillin G was begun, and complete resolution of the skin lesions was observed. A rapid plasma reagin titer test performed 3 months after treatment revealed a 4-fold reduction in the titer, indicating successful treatment.
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