Hello, I'm TV Tech1 and I'll be working with you to identify and help you resolve your problem.
The cartridge is a little more challenging, because several manufacturers provided cartridges and stylus for Pioneer. This fits the numbers you gave us --
PXV1003 seems to be the cartridge number, the PC-210 seems to be the STYLUS number to replace that. And unfortunately...the PXV1003 seems to be obsolete, unless you want to try this supplier --
I would phone them and not order it online. PXV1004 was a valid cartridge for the PL-Z91, and is listed in the part list --
But the other issue is the Cartridge TYPE.
Is it a P-Mount or 1/2" Mount cartridge you need??
Other option is to buy a different cartridge that fills your needs. http://www.styli.co.nz/cartridges.php
But the more important part is identifying Pmount versus 1/2" mount first. That helps us the most, knowing the TYPE