Case 133. Syphilis, primary (45 y-o M)

　 　 　 　
　
Biopsy from a painless penile ulcer
 　
　 　 　 　

　

 　 Highly coiled spiral microbes are easily demonstrated by immunostaining using a specific antiserum against Treponema pallidum. The spirochetae are localized in the intercellular space.