Late latent syphilis is latent syphilis where infection occurred more than 12 months ago. Latent syphilis can last for years. Tertiary Syphilis. Tertiary syphilis is rare and develops in a subset of untreated syphilis infections;, it can appear 10–30 years after infection was first acquired, and it can be fatal.
https://www.cdc.gov/std/syphilis/stdfact-syphilis-detailed.htm

