These are clinical features that could indicate breast cancer on a mammogram. It's a good sign that they didn't find anything on the ultrasound, but I'm confused what they want to biopsy if nothing showed on the US, and they said if nothing showed on the US, they'd wait and recheck?
But my advice, and I'm not a doctor or nurse, is to let them biopsy it, if you have any questions on this. You have a birad of 4, and it's better to know than wait and wonder.
These may help explain this: