What can you tell me about tertiary syphilis?

It's very rare: Syphilis occurs in 3 stages: primary (chancre, inflamed lymph nodes nearby), secondary (rash and other symptoms), and tertiary, or late syphilis, typically occuring 1-30 years later, with heart disease, neurological and psychiatric problems, and others. In the past 50 years, tertiary syphilis has been extremely rare (almost entirely absent) in the US and other industrialized countries.