Demonstration of Treponema pallidum in a cutaneous gumma by indirect immunofluorescence.

Treponema pallidum was demonstrated in a cutaneous, tertiary syphilitic lesion by indirect immunofluorescence microscopy, but not by darkfield microscopy illumination or silver stain. The numerous organisms observed by this method may help explain the histologically vigorous tissue reaction in tertiary syphilis, despite the scarcity of organisms demonstrable by other methods.