Pathology of Breast Tissue Obtained in Minimally Invasive Biopsy Procedures

Abstract

Over the last decade, minimally invasive biopsies, such as core-needle biopsies (CNB), have gained wide acceptance for the preoperative diagnosis of breast disease. Due to frequent fragmentation of the tissue and lack of architectural orientation, diagnosis based on this type of biopsy poses many problems for pathologists. Minimally invasive biopsy (MIB) in most cases allows for the decision of whether patients need to undergo additional surgical procedures including excision biopsy or even mastectomy. Pathologists establish the final diagnosis. Pathological examination is therefore one of the most crucial steps in the management of patients with breast disease. The decision process is mainly based on an accurate pathologic assessment, which also takes into account an appreciation of the differing biologic implications of the diverse entities observed. It must be kept in mind that many histopathological parameters have profound prognostic and predictive impact. In general, there is a difference between the pathological findings in biopsies from mammographically detected and readily symptomatic lesions. In MIBs from screen detection there is a diagnostic shift from frankly malignant to borderline and preinvasive lesions, which poses additional difficulties for accurate assessment. These lesions include premalignant breast disease such as columnar cell lesions, intraductal hyperplasia with or without atypia, lobular neoplasia, and ductal carcinoma in situ (DCIS). For example, recent studies have shown that columnar cell lesion with atypia (flat epithelial atypia) is often associated with DCIS and invasive carcinoma. Likewise, lobular neoplasia in needle core biopsies was followed by DCIS and invasive carcinoma in excisional specimens in as many as 25% of the cases. Papillary lesions of the breast have an association with invasive carcinoma, and excision biopsy is mandatory.