Percutaneous Breast Biopsies

As more women avail themselves of screening mammography, increasing numbers of breast biopsies for impalpable, mammographically detected lesions will be recommended. Ultrasonographically or stereotactically guided core (14G) breast biopsies are currently undergoing extensive evaluation as an alternative to excisional biopsies in the diagnosis of impalpable breast lesions. As a more cost-effective procedure, needle core breast biopsy is simple to do and associated with less morbidity than excisional biopsies. Appropriate uses and indications for stereotactically or ultrasonographically guided core biopsies continue to evolve. Impalpable masses and areas of parenchymal asymmetry that would otherwise go on to open biopsy are considered for core biopsy. If a mammographically detected mass can be seen with ultrasound, it may be easier and more convenient to do the core biopsy using ultrasound guidance. With stereotactic guidance we can also target and precisely remove calcifications one by one. Having the technology and expertise to accomplish this, however, does not make it the optimal method of managing patients with microcalcifications. With high—nuclear grade, comedo-type ductal carcinomain-situ (DCIS), the calcifications are molded by the tumor so that there is close apposition between the calcifications and the cancerous cells. When targeting casting-type calcifications, we are effectively sampling the cancer. The relationship between lownuclear grade, cribriform, micropapillary DCIS and microcalcifications, however, is not as definitive. In some of these patients the calcifications are not in direct association with the DCIS but rather with areas of proliferative breast change (ie, sclerosing adenosis, hyperplasia, and atypical ductal hyperplasia). The adequacy of cores in sampling the calcifications (particularly if not all calcifications are removed) and the surrounding tissue must be assured. Continuing discussion relates to issues of whether core biopsies should be done on microcalcifications and, if core biopsies of potential areas of low-grade DCIS are undertaken, the number of cores should be increased substantially to minimize the likelihood of sampling bias. At this point no definitive answers are available. It is incumbent upon all of us to approach "not clearly benign or malignant calcifications" with caution. Additional studies and long-term follow-up will be required to answer these questions more convincingly. Currently we do not recommend core biopsies on lesions thought to represent a radial scar—that is, spiculated lesions with central fat and long thin spicules alternating with fatty areas, having a differential appearance between orthogonal images and the absence of a corresponding palpable abnormality. Proliferative changes—including hyperplasia, atypical ductal hyperplasia, lobular neoplasia (AKA lobular carcinoma-in-situ), low-nuclear grade DCIS, and, rarely, tubular carcinomas—may be found in the spicules of radial scars. Although some pathologists may be able to characterize a lesion as a radial scar on needle biopsy, the diagnosis along is not the critical point. Removal and characterization of prognostically significant proliferative changes associated with radial scars are the critical points. So, when a radial scar is suspected preoperatively, or if a needle biopsy is inadvertently done on a radial scar, we recommend wide excisional biopsy without frozensection diagnosis. With mammographically malignant lesions a definitive histological diagnosis can be made on core biopsies. If a two-stage procedure (excisional biopsy temporally separate from the definitive surgical treatment) is planned, a core biopsy can eliminate the first step (open surgical biopsy) and facilitates the definitive surgical procedure. If a one-stage procedure is planned (diagnostic biopsy and definitive