Clinical significance of the entity 'flat epithelial atypia' on core needle biopsies of breast.

Abstract

Abstract Abstract #3006 Background: Flat epithelial atypia (FEA) is a newly emerging entity of uncertain clinical significance. Defined by the World Health Organization (WHO) in 2003, FEA differs from columnar cell hyperplasia by the presence of nuclear atypia and from atypical ductal hyperplasia (ADH) by the absence of complex architecture. As the term FEA is relatively new, the clinical relevance and the outcome data are sparse. The aim of this study is to evaluate the clinical and pathologic significance of this entity in order to construct the proper management of these lesions.
 Design: All core-needle biopsies (CNB) diagnosed as ADH, which includes pure FEA at our institution, from January 2006-April 2008 were retrieved from our pathology files. Hematoxylin and eosin (H&E) slides of five levels on each case were reviewed. Statistical analysis was performed with calculation of p-value.
 Results: Total number of CNB performed from 2006-2008 was 8054. 99% (8051/8054) were stereotactic guided and 1% (3/8054) were ultrasound/MRI guided biopsies. All the CNB were performed for microcalcifications. The mean age of the patients is 54 years (range 29-83). Incidence of ADH was 4% (338/8054). We have reviewed 203 cases so far and the study is ongoing. 32 cases were discarded due to either presence of DCIS or IC in the CNB. Upon review, 9% (18/203) cases were classified as pure FEA and 91% (185/203) cases as FEA+ADH. The upstaging to a significant lesion in pure FEA group is 14% in comparison to 12% in FEA+ADH group (p=0.9471), is not statistically significant. Lobular neoplasia is seen in association with pure FEA group in 33% (6/18) and 11% (21/185) in FEA+ADH group. In 6% (11/185) of cases in FEA+ADH group, we observed FEA evolved into ADH at the same site at an average of 3-4 levels.
 Conclusions: 1.The incidence of FEA in our CNB targeted for calcifications is 9% 2. The upstaging in the follow-up resections in FEA in comparison to ADH+FEA shows no statistical difference (14% versus 12%). 3. Since FEA and ADH commonly occur together on the same slide, it is prudent to examine deeper tissue levels when pure FEA is encountered on CNB. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3006.