Mammogram results

I just spoke with my GYN's nurse and was told that the doc wants me to have a diagnostic mammogram and ultrasound as a followup to the mammorgram I had a few weeks ago. When I asked for more infomation, I was told that no measuring had been done so she didn't know anything about size (Is that normal?) but that the report said there was a "mild to moderate thickening" in my left breast and "moderate conspicuous assymetrical density". She also said something about it saying "likely due to technical technique" which I assume means the way the mammographer performed the test and something about the report saying that it wasn't likely malignant, but those weren't the exact words she used. Nonetheless, I'm scared. I can't get an appt. till next Monday (which the nurse said was fine) but I want to do this ASAP. What does all of this actually mean?
I should also say that I have fibrocystic breasts but when I asked the nurse if that could be a factor she didn't really say anything. She kept talking about possible shadows and calcifications and "hoping for the best". Grrrr...

[CCF-RN,MSN-rf]

Dear amom2girlz:  It is not uncommon for a screening mammogram to turn up an abnormality.  Dense breast tissue can also make mammograms difficult to interpret.  A diagnostic mammogram and ultrasound may then be ordered to determine whether the abnormality is, in fact, present.  Sometimes, tissue folds over on itself and smoothes out when that area is focused on in a diagnostic mammogram.  An ultrasound is best at differentiating between solid and cystic masses.  It is impossible without reviewing the mammogram for us to speculate on how concerning this may be.  About 85% of people who are called back for diagnostic mammograms have benign (non cancerous) results.  

[DCM]

I will try to help as much as possible, since I just went through this process myself: please read my thread a few posts below yours: Lobular mass in Axilla - DCM
Because I also have extremely dense breasts, after the diagnostic Mamm & US I was referred a surgeon and he drained a cyst at the place of the mammographic mass suggested to be a lymph node after sonogram. Also had a core biopsy that I will have to repeat in 6 months. Diagnostic on core needle biopsy of 4cm: "dense interstitial fibrosis" with no hyperplasia - benign.
However, the surgeon will have another mamm in 6 months and if the lump does not decrease (apparently it did not go away by FNA, even if I do not feel it anymore) he will take it out surgically. As most on this site, I would say : go and do all tests required, and if you have the slightest doubt in results, please go and see a specialized surgeon: they are the only ones that will actually give you the ultimate answer and reassurance.
The hours before appointments - no matter how reassuring all were around me - were still the hardest part... but they are behind now, and I have a better understanding of things to do... plus I got the chance to read other posts on this site that educated and helped me to get over anxiety.
All the best to you.
DCM