An excisional breast biopsy refers to removing an abnormality within the breast. A lumpectomy, also called a partial mastectomy, refers to removing a breast cancer. When a suspicious breast abnormality or cancer is found by imaging and cannot be felt by hand (palpated) the surgeon, the surgeon needs a method to identify where in the breast the lesion is. 

To help the surgeon find exactly where to remove the abnormality or cancer when it cannot be palpated, a localization procedure is performed prior to the surgery. Most commonly, a wire is placed into the breast using a needle as the way to guide the surgeon to the precise location of the abnormal breast tissue or cancer. 

The needle containing a hooked wire is placed into the breast under local anesthesia, usually on the same day of the localized excisional breast biopsy or lumpectomy. Once the needle and wire are in the proper position in the breast, the needle is removed, leaving the wire in place, localizing the site. The opposite end of the wire will stick out of the skin and will be secured with gauze and tape. Then, in the operating room, the surgeon removes the suspicious lesion or the cancerous tumor, using the wire as a guide at all times. A landmark in the breast marks the spot for placement of this wire, such as small calcium deposits, a biopsy marker or clip, or a suspicious finding only seen on mammogram or ultrasound. 

Essentially, anything deemed necessary to remove from a breast that otherwise is not palpable, can be excised using this technique. Once the wire-localized lesion is removed, the specimen containing the wire is sent for a specimen X-ray to prove that the abnormality or cancer was properly removed. 

There are new technologies emerging utilizing sophisticated devices for localization of breast lesions. Small radioactive seeds can be placed safely in the breast at the site of the abnormality or cancerous tumor, and a probe is used to find the location of the seed at the time of surgery. Similar devices use a radio signal, rather than radioactivity, for localization lumpectomy. These new techniques eliminate the use of a wire, and can generally be placed many days prior to the surgery date.