Atypical ductal hyperplasia on vacuum-assisted breast biopsy: suspicion for ductal carcinoma in situ can stratify patients at high risk for upgrade.

We evaluated 97 cases of review-confirmed atypical ductal hyperplasia found on stereotactic vacuum-assisted breast biopsy of suspicious calcifications. The number and size of foci of atypical ductal hyperplasia and presence of a micropapillary component were noted. In addition, we recorded if a case was considered "atypical ductal hyperplasia suspicious for ductal carcinoma in situ" using specific qualitative criteria. The upgrade rate was 20.6% (20/97) for all cases and 48% (12/25) for cases suspicious for ductal carcinoma in situ. Suspicion for ductal carcinoma in situ was found to be a strong predictor of upgrade with an odds ratio of 7.4 (P = .0003). Suspicious cases with nuclear features bordering on intermediate nuclear grade had the highest upgrade rate of 75% (6/8). Cases with ≥ 3 foci had significantly higher upgrade rates (28%) than those with less than 3 foci (11%), but focal atypical ductal hyperplasia did upgrade (P = .04). In conclusion, qualitative features of atypical ductal hyperplasia on core biopsy such as suspicion for ductal carcinoma in situ may help stratify patients at the highest risk for upgrade.