Back in the Pentium days it was a CPU pin which would go active on "Processor Hot" ... perhaps Intel still uses that term (and pin) today?
The extreme temperature you are seeing only on one location, assuming all continues to run OK, sounds like a faulty sensor to me.
Perhaps the Relative to ProcHot is the number of Degrees F or C that you are FROM the maximum allowable temperature (TJmax?). My Prochot number DECREASES as my Tdiode increases.
That would put your T Diode's maximum 'safe' temperature at 234F (or 111C) more or less (91F + 143F). I presume that this is the temperature at which your system would shut itself down to prevent damage from overheating.
I always understood that anything above 100C was too hot.
If all of this is the case, then the high number that you see (for Relative to Prochot) is possibly a good thing.
Try stress-testing the CPU and see what the 'CPUA Relative' temperature does. Open Terminal and type: yes > /dev/null &
Do several of these until your CPU cores are being heavily utilised.
To stop the testing, type: killall yes