Incidental minimal atypical lobular hyperplasia on core needle biopsy: Correlation with findings on follow-up excision

INTRODUCTION: Atypical lobular hyperplasia (ALH), often an incidental finding in breast core biopsies, is largely considered to be a risk factor for carcinoma rather than a direct precursor. However, management of ALH is controversial. We review our experience with incidental minimal ALH on core biopsy, and correlate with excision and follow-up results. DESIGN: We evaluated all cases of ALH on core biopsy from 1999 to 2009 from our institution, focusing on cases with ≤3 foci of ALH (minimal), paired excision, and no other lesion on the core biopsy that by itself would require excision. Cases with discordant clinical/radiologic impressions, suggesting that a suspicious lesion had been missed on biopsy, were excluded. Therefore, the excisions were performed because of the diagnosis of ALH. RESULTS: Of 56 cases with ALH on biopsy and paired excision, 42 showed minimal ALH. On excision, 26 had residual ALH and 13 were benign. Three cases had other atypical lesions: lobular carcinoma in situ (2 cases) and mild atypical ductal hyperplasia separate from the biopsy site (1 case). On follow-up, only 1 patient developed subsequent ALH in the same breast. No other ipsilateral lesions were later diagnosed (mean follow-up 3.2 y). CONCLUSIONS: No case with ALH on biopsy had a lesion on excision requiring further treatment, suggesting that these patients can be managed more conservatively. Furthermore, no patients were diagnosed with a higher grade lesion in the same breast on follow-up. We propose that, if there is close radiologic correlation and follow-up, minimal incidental ALH on core biopsy (≤3 foci) does not require excision.