MMMM that looks like it may be a problem with a Windows Font. I am not sure what font lol uses for those areas specifically though so I have no idea which one you should reinstall... You *could* open up Wordpad or google docs and go through all your fonts one at a time to make sure they are all working.
LoL does not really need to use cutom fonts for everything, they could easily pull one from the Windows library. Of course, you may want to try reinstalling LoL anyway, just remove it completely, reboot your machine then download and reinstall it from scratch.