Can new microcalcifications be part of scarring from breast reduction 18 months ago

I had a BR in Jun 2010 and am very happy with the results but I have had hard/firm spots for, which have been decreasing.  My 2nd mammo post surgery, was a Birad 4 with an irregular nodular density with cluster of microcalcifications that are new from last mammo.  Can this be fat necrosis or scarring?  They have identified 2 area of fat necrosis, but this one area is suspicious.  How long can fat necrosis continue for or can it be new fat necrosis for some reason. I am having a biopsy, am hoping it is some fat necrosis