Introduction Triple-negative breast cancer (TNBC) lacks expression of the estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor 2 (HER2) and accounts for approximately 15% of invasive breast cancers (IBCs) among screened individuals and up to 20% to…
IDC, or ductal carcinoma of no special type (ductal NST), is a heterogeneous group of tumors that fail to exhibit sufficient characteristics to achieve classification as a specific histological type, such as lobular, mucinous, or tubular carcinoma ( Fig. 23.1…
Ductal carcinoma in situ (DCIS) is a heterogeneous group of lesions defined as a proliferation of neoplastic epithelial cells within the mammary duct lobular system. Major diagnostic criteria that differentiate DCIS from invasive cancer are the presence of intact basement…
Despite the earlier descriptions by Ewing, the term lobular carcinoma is largely credited to Foote and Stewart, who, in 1941, published their seminal paper describing a detailed morphological analysis of a distinctive subgroup of in situ carcinomas of the breast,…
Introduction: Screening and Detection As the imaging modalities used for breast cancer screening and diagnosis have improved, the types of specimens evaluated by pathologists for risk-associated lesions have changed. In contemporary practice, atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia…
Fibrocystic change (FCC) refers to a complex of lesions including gross and/or microscopic cysts, apocrine metaplasia, fibrosis, and blunt duct adenosis (BDA), and minor degrees of sclerosing adenosis and usual epithelial hyperplasia. It is important to realize that cystic change…
The epithelial system of the breast consists of a ductal system and terminal ductal lobular units, both of which are lined by two cell layers: an inner layer of luminal epithelial cells facing the lumen and an outer layer of…
The term radial scar (RS) was first coined in the 1980s in a German paper by Hamperl. Page and Anderson first suggested using the term radial scar for lesions measuring up to 9 mm and the term complex sclerosing lesion…
Introduction The term adenosis is used to describe a non-neoplastic lobulocentric proliferation of ductules with epithelial and myoepithelial cells, usually formed from the terminal duct lobular unit. The clinical presentation is variable and numerous microscopic variants have been described. Most…
Introduction For diagnosing a majority of breast lesions, a high-quality hematoxylin-eosin (H&E) stained section is all that is needed. However, in our quest for improved diagnostic accuracy, immunohistochemistry (IHC) is frequently used in diagnostic breast pathology. The sheer volume and…