Mickie, the comment about the bilateral dense tissue sounds like just a description of your breast tissue that doesn't represent anything to worry about.  Although breasts are not perfectly symmetrical, one way that radiologists read mammograms is by comparing both sides.  When they see an area on one side that isn't on the other (not symmetrical), they like to take a closer look.  It takes a trained radiologist to decide if the area of asymmetry needs more investigation.  Since more tests have been ordered, it sounds like the radiologist wants a better look at the area that looks different from the other side.  It could turn out to be a tumor, or it could just be your normal pattern.  If you have old mammogram images, it will be important for the radiologist to check them out to see if this area has always been there.  Since the report says the area is small, if there is a problem, it sounds like it has been caught early.