cluster of microcalicification

I had a mammo and ult and spot compression, first one and it showed cluster microcalification 1/3 left breast, needle bx recommended. The radiologist put cat. 4 on report. What does that mean, the rating 4. I went to see a surgeron today who didn't seem that concerned but maybe that was for my benefit. She recommened three things, one wait 6 months repeat mammo and compare, needle bx or bx with tissue removal which I chose the latter. please help me interpret. thank you

[CCF-RN,MSN-JS]

Dear di56, In an attempt to standardize the reading of mammograms a system was developed categorizing findings on a mammogram.  The categories range from 1-5 with 1 being a negative finding, and 5 being highly suggestive of malignancy.  A category 4 describes a suspicious looking abnormality, which means it is not characteristic but has reasonable probability of malignancy, and a biopsy should be considered.

Briefly as you have noted your choices are 1) waiting six months to see if there is a change.  2) A needle biopsy which, is the least invasive method of obtaining a sample, however there could be a chance that an abnormality is missed. 3) The biopsy incorporating more tissue which is more invasive but with more tissue less chance of missing an abnormality.  Ultimately the decision of what to do will be up to you after discussion with your surgeon and understanding the risks and benefits of each choice.  Another option is to get second opinion from another well-qualified breast surgeon.