Review Question - QID 108767

A 60-year-old female presents to her gynecologist with concerns about a mass she felt in her right breast on self-examination. She denies pain, redness, or nipple discharge in the affected breast. She denies a family history of breast cancer. Physical examination is notable for a firm, immobile mass in the superolateral quadrant of the right breast. No skin changes or axillary lymphadenopathy are noted. Her left breast has no significant findings. A biopsy of the lesion is performed and an H&E stained slide is shown in Figure A. Which of the following is the most likely explanation for the histologic appearance of the specimen?