tissue density

I am 45 years old and had a mamogram (mammogram).  I was asked to return bec the radiologist saw soft tissue density on one of the breasts.  I am very concerned. What can this mean?

[Cleveland Clinic]

Dear etti:  It is not uncommon for a density to show up on a screening mammogram.  When this happens, the radiologist will typically call the woman to come back for spot compression where a more specific view of the abnormality can be obtained.  In many cases, the density could be as simple as some tissue that has folded over on itself and will resolve with compression.  However, the spot compression will take a closer look and help to determine if there is an abnormality and whether any additional evaluation is necessary.