A 60-year-old woman is noted to have a 2-cm mass in the left breast. The patient’s physician recommends that a core needle biopsy be performed. Tissue analysis by the pathologist under the microscope reveals intraductal carcinoma. The patient is advised by the surgeon to have surgery to remove the primary breast mass in addition to some lymph nodes. The patient undergoes wide excision of the breast mass and lymph node removal.