A total of 143 breast biopsies were compared with xeroradiographic images. N1 breasts showed normal stroma, ducts, and lobules; P1 breasts had mild to moderate perioductal and perilobular fibrosis with some atypical lobules and other low-grade lesions; P2 was similar to P1 but with more fibrosis and higher-grade atypical lobules; and DY was generally similar to P2 but with more high-grade atypical lobules and extensive, confluent fibrosis. The highest grades of precancerous epithelial abnormality appear to be found in P2 and DY, seldom in P1, and very rarely in N1. Xeroradiographic and histological risk grades show very close correlation.