I am 41y/o female just recently had my third mammogram “always normal” however last year they said my breast was denser than average, and to make sure I have a mammogram every year.
My most recent mammogram was done 05 July 2007; I received a letter 19 days after my mammogram.

I might add, we are military, and currently living in Okinawa, Japan

The letter reads as follow

There is an area on your bilateral mammogram that requires further evaluation. The radiologist recommends that you return for special views of the right breast and an ultrasound examination of the right breast. Ultrasound is sometimes necessary in order to obtain a more definite diagnosis than that provided by standard imaging alone.

They said they sent the results to my doctor, but I had not heard a word back from my doctor, so I am freaking out. I tried making an appointment with my doctor, but she is completely booked up, and she is preparing to leave soon.

Therefore, I emailed her, she did respond back rather quickly, and this is what she wrote

It appears there MAY be a 5mm (you would not be able to feel it) nodule seen only on one view of the mammogram. That is why they need you back, because it they cannot confirm it on other views, it is probably a nothing. So, I would get the repeat mammogram and wait to see what if they can see it on other views, or they may do an ultrasound to help confirm it.

I am really freaking out; I do not really understand the 5mm part. Can somebody please explain what they may be talking about?