The challenge here is to establish if you are looking at entrapped fat or fibroadenomas. I can usually use the echotexture of the lesions to determine fat from fibroadenoma but there are occasions where this is difficult. Use the other native breast fat as a reference point and compare exhotexture and echogenicity. Use SMI or ADF as a fibroadenoma will often be vascular whereas fat is not. Use the compressibility of the area as a guide as a fibroadenoma is firmer than entrapped fat. I wonder if elastography may have a role here??
Finally, palpate the area as fat will be soft and a fibroadenoma will feel firm.
If there is sufficient doubt, treat the area as a solid mass and perform a biopsy. The worst thing that can happen is a biopsy of normal breast fat. Being cautious and defensive is always a good strategy with ultrasound