The basic pathology of human breast cancer

This article illustrates the most common benign and malignant lesions in th e breast, and is intended for the biologist working in the area of breast c ancer and breast biology, not for the practicing pathologist. The atlas cov ers benign proliferative lesions, atypical lesions, variants of in situ can cer, the main types of invasive cancers, spindle cell lesions, and examples of vascular and lymphatic spread. Some entities are included to illustrate a point of particular relevance to the biology and histogenesis of the les ions. Some controversial diagnostic areas are considered, along with the re lative risk of developing breast cancer associated with some of the prolife rative lesions. The content of this atlas should be read in conjunction wit h the companion article by Howard and Gusterson in this issue. Their articl e covers the cellular origin of epithelial and stromal tumors and presents a description of some of the common benign proliferative lesions that are c onsidered to be components of the normal spectrum of changes seen at postmo rtem or in biopsies.