Case 61 Answer
In case you still don't know what this finding is, here is a magnification view:
This patient was recently treated for a collagen vascular disease, and had her Hickman Catheter removed six minths ago. Since then, she has has intermittent swelling and tenderness of the palpable area which shows a retained Hickman cuff and an irregular area of surrounding fluid. The cuff is likely infected, and is acting as a nidus. We referred her to a surgeon to have it removed. Thus the correct answer is BIRADS 2, Benign. Recommend referral to a surgeon.
If you saw the cuff on the original mammogram, you might have been tempted to say that the lump is the cuff and an ultrasound is not necessary. But the cuff does not really explain the fluctuation in size, and it is helpful to show that the lump actually does correlate with the cuff with ultrasound. Usually, if you feel the cuff at all, it is a small firm nodule about 1cm in size.