There are some more precise stains for the biopsy samples that help identify tissue. There may have been questionable samples. It may just be that you have a good uro. That sort of extra testing should be normal procedure, but rarely is. Don't hesitate to ask the doctors what they are doing.
I don't have details on the stains, but I'm sure several of the guys here can give you a description.
Welcome to HW. I hope it turns out that you don't need to be here, but if you do, the light is on in the window.