Worried about sisters mammogram results

My mom who is 67 was diagnosed with stage 1 breast cancer and thankfully it has been removed and her prognosis looks great per her doctor.  Now my sisters, one who is 39 and the other 42 had their annual mammograms done were told the following:
39 yr old;  density on right breast - needs a diagnostic mammo
42 yr old:  intrammomary lymph node
Please explain what that means and should we be worried?

[OnTheCouch]

An intramammary lymph node is simply a lymph node - you have them all over your body - that is inside the breast tissue.  It's not any kind of cancer, just a normal body part and nothing to worry about.

A density on your other sister's breast simply means that there is a shadow, or denser area on the mammogram film.  The most common cause is simply that the normal tissue was "folded" and caused that one area to appear darker than the rest.  They want her to have a diagnostic mammogram so that they can look at the same area again and see whether the area disappears when the tissue is no longer folded.  If it's gone, then everything is fine and it was only a matter of the technique of the person who did the mammo.  If the density remains, then the odds are still very slim that it's breast cancer - there's a million other things that it would be.  

No matter what I tell you, I realize that it's going to be difficult for not to worry about yours sister, but why not try this:  reserve your worrying until after the diagnostic mammogram.  Honestly, odds are that it's nothing.

[soccermom2]

Thank you so much for responding.  As a matter of fact, both my sisters got their results and everything is okay.  You were right!  Again, thank you for your reasssuring words.