This is a surgical excision performed in the operating room after an abnormality, lump or calcification, is identified by needle biopsy. Radiologists place a wire into the lump or calcification using mammogram or ultrasound guidance; the wire helps surgeons find the area of concern at the time of surgery. Additionally, the UW Breast Center is one of the few centers in Wisconsin that also uses MRI to guide the placement of the wire for the surgical biopsy.