A 38-year-old client presents to the clinic office complaining of increased bilateral tenderness of her breasts prior to the onset of menses. On questioning the client, this presentation has occurred off and on for several years, but the pain has increased. Physical examination reveals lumpy areas bilaterally on the upper outer quadrants of each breast tissue. The areas of concern are approximately 2 cm in size. Based on this assessment, what diagnostic testing would be required?