Neoplasia USMLE Step 1 Practice Question

A 45-year-old woman presents to her primary care physician after mammographic screening identifies a 1.2 cm mass in the left breast. She reports discovering a small amount of bloody nipple discharge from the left breast 2 weeks ago, which prompted imaging. Vital signs are stable. Physical examination reveals no skin changes, dimpling, or axillary lymphadenopathy. A core needle biopsy is performed. Histopathology shows a benign proliferation of epithelial cells arranged around a fibrovascular core, with intact myoepithelial cells surrounding the lesion and preserved basement membrane. Which of the following is the most likely diagnosis?