Background: Small nonpalpable mammographic abnormalities are frequently diagnosed by percutaneous stereotactically guided core needle biopsy. The reliability of the histologic diagnosis of atypical ductal hyperplasia (ADH) made from tissue obtained by 11-gauge directional, vacuum-assisted biopsy of these nonpalpable breast lesions is unknown.
Methods: The records of 31 patients who were found to have ADH by 11-gauge directional vacuum-assisted biopsy were reviewed. All of these patients subsequently underwent surgical excision with needle localization biopsy of the ADH and they are the subjects of this retrospective study.
Results: Eleven of the 31 patients with ADH on 11-gauge directional vacuum-assisted biopsy were upgraded to ductal carcinoma in situ or infiltrating carcinoma by the excisional biopsy. This was a 35% underestimation of malignancy in our patients.
Conclusions: When the histologic diagnosis of ADH is made from tissue harvested by an 11-gauge directional vacuum assisted biopsy, surgical excision of the entire abnormality is recommended to avoid underdiagnosis of breast cancer.