Lynn, it's wonderful that your doctor is looking out for you and being proactive about getting this checked out.  It is much too early to panic.  If your doctor was really worried, she probably would have ordered a diagnositic mammogram.  I didn't realize that bone density screening would pick up breast issues, but the term fibroglandular sounds like these would be the kind of breast changes that are very typical and not dangerous.  Your doctor probably just wants to be sure that's all they are.  Follow up with the mammogram, and if they find something that needs more investigation, keep in mind that the vast majority of biopsies are benign.