Purpose: To ascertain the frequency and pathologic relationships of atypical hyperplasia in biopsy specimens obtained after clinical and mammographic examination.
Materials and methods: Clinical, mammographic, and histologic findings were prospectively correlated in 300 consecutive excisional biopsies.
Results: Atypical hyperplasia was detected in 26 (17%) of 154 biopsies with benign findings and 19 (13%) of 146 biopsies with malignant findings overall (P > .05). The frequency of atypical hyperplasia was only 4% (two of 55 specimens) in clinically prompted biopsies with benign findings but 24% (24 of 99 specimens) in mammographically prompted biopsies with benign findings (P = .002), increasing to 31% (21 of 68 specimens) in benign microcalcifications and 40% (18 of 45 specimens) in benign microcalcifications associated with adenosis. Atypical hyperplasia was found most often within (16 [62%] of 26 cases) or adjacent to (nine [35%] of 26 cases) another lesion that prompted biopsy.
Conclusion: Most atypical hyperplasia is not a random finding in benign biopsy specimens but shows a statistically significantly greater frequency in association with microcalcifications detected with mammography only, especially those in areas of adenosis.