[138] 'Flat Epithelial Atypia': Impact of the Entity with Reference to Number of Levels Obtained on the Paraffin Embedded Blocks of the Breast Core Needle Biopsies

M Chivukula, R Bhargava, G Tseng, DJ Dabbs. Magee-Women's Hospital of UPMC, Pittsburgh, PA; University of Pittsburgh, Pittsburgh, PA

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 was to evaluate the pathologic significance of FEA with reference to number of levels obtained on the paraffin blocks of the core needle biopsy samples (CNB).
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 significance defined as p-value of <0.05.
Results: Total number of CNB performed from 2006-2008 was 8054. Ninety nine percent 99% (8051/8054) were stereotactic guided and 1% (3/8054) was 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 (including FEA) was 4% (338/8054). Slides from 203 cases were available for review. 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. 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. The upstaging to a more clinically significant lesion in pure FEA group is 14% in comparison to 12% in FEA+ADH group (p=0.9471). Lobular neoplasia seen in association with pure FEA group in 33% (6/18) and 11% (21/185) in FEA+ADH group.
Conclusions: 1. The incidence of FEA in our CNB targeted for calcifications is 9% 2. 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. 3. The upstaging in the follow-up resections in FEA in comparison to ADH+FEA shows no statistical difference.
Category: Breast

Monday, March 9, 2009 11:15 AM

Platform Session: Section B, Monday Morning