First of all i'd get the test confirmed by your doctor or gyn.
Are you on any treatments/meds that contain hormones for the endo?
Did you think you might be pregnant?
Then it comes down to you.
If you are pregnant do you want this child even?
You can go ahead with the hyst if you don't want the pregnancy or you can re-schedule the hyst to be done at the time of the birth if you'd rather.
Best thing is to discuss your options with your doctor.