In recent years, core needle biopsy has become an integral part of the triple approach for the diagnosis of breast cancer lesions in screening programmes. This technique has undoubtedly changed diagnostic breast pathology practice and new diagnostic challenges have emerged. This issue of the Journal of Clinical Pathology contains a series of reviews addressing troublesome areas of non-operative breast pathology, including columnar cell change and flat epithelial atypia, lobular neoplasia, apocrine change and hyperplasia, ductal hyperplastic and neoplastic lesions, and metastasis to the breast, written by diagnostic breast pathologists based in the UK. The aim of this series of reviews is to provide an update on recent clinicopathological, immunohistochemical and molecular data on these rather difficult lesions and offer some guidance as to how these lesions should be managed.

With the advent of the National Health Service Breast Screening Programme (NHS BSP) in the late 1980s, the ethos of obtaining a preoperative (or non-operative) diagnosis of breast abnormalities became firmly established and subsequently has been applied to both symptomatic and screening practice; frozen section diagnosis as a routine for breast lesions is a largely historical technique in the UK. The highest levels of accuracy in breast non-operative diagnosis are achieved using the triple approach, combining imaging and clinical examination assessment with pathological results; it is worth emphasising that fine needle aspiration cytology (FNAC) and core biopsy diagnosis from impalpable lesions should not be interpreted in isolation, but it has been recognised for many decades that a combination of the three disciplines results in accuracy of over 99%.1 The non-operative identification of the nature of a lesion in the breast, by either FNAC or core biopsy, allows rapid diagnosis and subsequent discussion with the patient regarding treatment options, including the benefit of avoiding unnecessary surgery …