Background and objectives: To characterize both atypical hyperplasia (AH) and the malignancies typically present at open surgical biopsy in women diagnosed with AH by stereotactic core needle biopsy (SCNB).
Methods: Patients with AH diagnosed by SCNB were advised to undergo surgical biopsy to rule out an associated malignancy. Mammography findings, pathology reports and follow-up data were analyzed.
Results: AH was identified by SCNB in 38 of 893 (4.3%) patients. Carcinoma was identified in 12 of 33 (36.4%) patients who went on to surgical biopsy. Ductal carcinoma in situ (DCIS) was present in 11 of the 12 patients with malignancy. There were no characteristic mammographic findings which would identify patients with carcinoma.
Conclusions: When SCNB returns a diagnosis of AH there is a substantial risk of an associated malignancy in the breast. There appear to be no definitive criteria to distinguish which patients harbor a malignancy, and surgical biopsy should always serve as an adjunct diagnostic procedure.