Pathological aspects of core needle biopsy for non-palpable breast lesions

Recently, the incidence of non-palpable or noninvasive breast cancer has increased. Consequently, criteria for choosing procedures to obtain pathological materials had changed. Fine needle aspiration biopsy cytology (FNA) and core needle biopsy (CNB) are both reliable procedures for detecting breast cancer. However, for non-palpable lesions, the diagnostic accuracy of CNB is higher. The main limits of FNA are the high rate of insufficient sampling and inability to determine invasiveness. CNB is an established alternative to surgical biopsy, and CNB can avoid excess surgical biopsies in a large number of patients. In addition to accurate histological diagnosis, there is interest in obtaining prognostic information from CNB, especially for patients being considered for preoperative (neoadjuvant) therapy. CNB provides useful information about histologic type and grade. However, an unavoidable problem of CNB is underestimation of invasion. On the other hand, there is good concordance in particular for estrogen receptor (ER) and progesterone receptor (PR) between CNB and surgical excision. Several aspects of CNB remains controversial, such as diagnosing papillary lesions by CNB, problems regarding tumor cell displacement after CNB, and management of lobular neoplasia (LN) on CNB.