There is a broad spectrum of benign and pre-malignant breast disease that m
ay be diagnosed on biopsy. Some of these conditions place affected women at
significantly increased risk for breast cancer, particularly the atypical
hyperplasias. All health care workers should be aware of recent development
s in this important aspect of breast disease. The classification, criteria
for diagnosis, associated risks for cancer development and various controve
rsies related to these benign and borderline breast diseases are discussed.