I had exactly the same thing and a couple of weeks ago had an ultrasound, where it was confirmed I had a couple of tiny cysts. I don't know the exact percentages, but the chances of a lump on the testicles NOT?? being anything sinister are in the high 90s....and anything on or next to the tube is almost certain to be a cyst or similar.
Maybe she just wants to double-check it herself, as she wasn't there the first time? Ultrasounds are extremely accurate so I think it's seriously doubtful that there's anything to worry about. I'm sure your mind will be put at rest very soon