Review Question - QID 109840

A 35-year-old woman presents to her primary care doctor for a right breast mass that was found during self-exam. Her paternal aunt had been diagnosed with breast cancer 5 years ago, so she wishes to undergo further oncologic evaluation. She is currently training for professional triathalons. She denies any sexual activity and reports that her last period was about 2 weeks ago. Her temperature is 99.5°F (37.5°C), blood pressure is 110/58 mmHg, pulse is 58/min, respirations are 12/min, and oxygen saturation is 98% on room air. On physical exam, a small mobile non-tender mass is palpated in the inferolateral quadrant of her right breast. Mammography is shown in Figure A. The doctor recommends a fine needle aspiration biopsy, which demonstrates fat globules, hemosiderin-laden macrophages, fibrotic tissue, and foamy histiocytes. What is the most likely diagnosis?