Atypical ductal hyperplasia in directional vacuum-assisted biopsy of breast microcalcifications: Considerations for surgical excision

Background. Our goal was to analyze clinicopathologic features of patients with atypical ductal hyperplasia (ADH) diagnosed on directional vacuum-assisted biopsy (DVAB) targeting microcalcifications to identify factors predicting the presence of carcinoma. Materials and Methods. We retrospectively evaluated the clinical, mammographic, and histologic features of 140 patients with DVAB-diagnosed ADH who underwent either segmental excision (86.4%) or mammographic follow- up (≥2 years; 13.6%). Cases with mass lesions or ipsilateral cancer were excluded. Results. In 16 cases, carcinoma was found on excision. All cases without excision showed no new abnormalities on mammographic follow-up. Only the amount of calcifications removed (≤95%) significantly correlated with the rate of upgrade of ADH to carcinoma (P = .037). Significant histologic predictors of upgrade to carcinoma included number of terminal duct-lobular units (TDLU; >2) involved (P = .0306), presence of significant cytologic atypia suspicious for intermediate or high-grade carcinoma (P<.0001), and necrosis (P = .0006). Among ADH cases without significant atypia and/or necrosis, the extent of ADH (≤2 vs. >2 TDLU involved) was not a significant predictor of carcinoma (P = 1.0000). Conclusions. ADH associated with calcifications in the absence of a mass lesion can be categorized into different risk groups using a multidisciplinary approach with correlation of histologic and mammographic findings. ADH lesions with significant cytologic atypia and/or necrosis are most likely to be associated with carcinoma and should be excised. ADH without these features, regardless of extent of involvement, and with >95% removal of the targeted calcifications, is associated with a minimal risk (<3%) of carcinoma and may undergo mammographic follow-up only.