OK what is a shadowing? How old are you? If you are young and have dense breasts you should have a sonogram. Take no chances, especially with history in your family. If you have a breast specialist in your area I think it would be a good idea that you make an appointment. They understand more about shadowing, lumps, calcifications, etc. than a family doctor and perhaps the radiologists. Do not just let it go and forget about it. Breast cancer is best treated found early. I don't mean to scare you but with family history I would be VERY careful of everything you find that might be chancey. Take care of yourself! Keep copies of all reports in a safe place and together. I am still looking for some reports I had that somehow got packed separately when we moved........... grrrr. You never know when you might want to refer back to them.
Hugs Mary K.