Flat Epithelial Atypia Of The Breast: A Single Institution Experience.

Background: Flat epithelial atypia of the breast is a relatively new entity of unknown significance. Our objective is to evaluate our surgical experience with this diagnosis. Methods: A single institution database of breast patients from 2005–2010 was used to identify women who were diagnosed with flat epithelial atypia on core biopsy and subsequently underwent surgical excision. Patient data regarding history, type and reason for biopsy, and associated pathology was collected. Individuals diagnosed with flat epithelia atypia and cancer on core biopsies in the same breast were excluded. Results: There were 52 patients who underwent surgical excision for the primary diagnosis of flat epithelial atypia. There were 3 (6%) patients with a personal history of breast cancer, 14 (27%) patients with a family history of breast cancer, and 11 (21%) patients with a concurrent new diagnosis of breast cancer in the contralateral breast. Core biopsy was recommended in most (81%) cases because of suspicious calcifications on mammography. Twenty-eight (54%) patients were found to have flat epithelial atypia associated with other atypical breast hyperplasia and 24 (46%) had flat epithelial atypia as the most significant lesion on core biopsy. In 8 (15%) patients, there was a sonographic correlate that was biopsied; 5 had only flat epithelial atypia and 3 had flat epithelial atypia associated with other atypical hyperplasia. Of the 52 patients there were 4 (8%) patients who upstaged to ductal carcinoma in-situ on surgical excision. There were no cases of invasive carcinoma. All ductal carcinoma in-situ cases were associated with other atypical breast hyperplasia, not flat epithelial atypia alone. Conclusion: Though flat epithelial atypia may be associated with an increased risk of breast cancer, surgical excision of pure flat epithelial atypia may not be necessary. Larger studies are needed to corroborate these findings. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-11-14.