Objective: To determine the degree of histologic sampling necessary for adequate examination of breast core needle biopsy specimens.
Design: The results of all breast core needle biopsies (11 and 14 gauge) with a diagnosis of atypical small acinar proliferation or atypical ductal hyperplasia and subsequent excisional biopsies, for a 50-month period were reviewed. Blocks of all cores were sectioned entirely in 8 slides to determine the amount of sectioning needed to detect these foci, and the results were correlated with those from the excision specimen.
Setting: Large community hospital practice.
Results: Of 3026 cases, 216 (7.1%) were diagnosed as atypical ductal hyperplasia or atypia not otherwise specified. Subsequent resections were available in 105 (49%) cases, and after review, 95 (92%) qualified as atypical ductal hyperplasia and 2 were determined to be atypical small acinar proliferations. The 2 small acinar proliferations were first detected on the second and fourth slides. Of the atypical ductal hyperplasia cases, 43% were detected on the first slide, 17% on the second, 23% on the third, 8% on the fourth, and 8% on the fifth. No lesions were initially detected after this level. Ductal carcinoma in situ was detected in the excision specimens from 1 case each of those detected initially on the fourth and fifth slides.
Conclusion: Five sections of breast core needle biopsy specimens are necessary to ensure that all atypical small acinar proliferations and atypical ductal hyperplasia lesions are sampled.