A woman presents to the breast clinic after having noticed a palpable lump in her left breast. The lump is mobile and feels well defined to palpation. Mammogram demonstrates a well circumscribed oval mass that is of a similar density to the glandular tissue. Ultrasound also shows a well-circumscribed lesion that is uniformly hypoechoic, with a thin echogenic rim.

Which of these is the weakest indication for biopsy?