Atypical ductal hyperplasia diagnosis by directional vacuum-assisted stereotactic biopsy of breast microcalcifications. Considerations for surgical excision.

In 824 patients who underwent directional vacuum-assisted biopsies (DVABs) of breast microcalcifications, 61 (7.4%) showed atypical ductal hyperplasia (ADH). The 42 who subsequently underwent excision were the subjects of this study. Cases were evaluated for the mammographic characteristics of the lesion, the percentage of lesion removed according to mammography, and histologic findings (including number of large ducts and/or terminal duct-lobular units involved with ADH) in DVAB specimens. Pathologic findings in the surgical specimens in the area of the biopsy site also were recorded. In the DVAB specimens, ADH was confined to an average of 1.5 large ducts or lobular units and was associated with microcalcifications in all of the patients. Surgical specimens showed ADH in 15 cases, no residual lesion in 24 cases, and ductal carcinoma in situ in 3 cases. We found that microcalcifications that contain ADH in less than 3 lobules or ducts and/or that are removed completely by DVAB do not reveal higher-risk lesions on excision; thus, removal is unnecessary. When assessing microcalcifications with ADH, clinicians should consider the percentage of microcalcifications removed by DVAB and the extent of lobular involvement to better assess the need for excision.