Flat epithelial atypia: biological significance on core biopsy

Introduction

Flat epithelial atypia (FEA) is seen with increasing frequency following biopsy of calcification detected through screening. FEA is often associated with more significant lesions including atypical ductal hyperplasia and ductal carcinoma in situ (DCIS). It is postulated that FEA may even represent the earliest morphological manifestation of DCIS and a precursor to invasive carcinoma. However, the significance of pure FEA still remains unclear. We aim to review the radiological and pathological features of FEA and evaluate the significance of FEA on needle core biopsy.

Methods

We performed a retrospective analysis of all needle core biopsies containing FEA in the pathology database from April 2008 to April 2010. For each case the following data were recorded: mammographic features, method of further sampling (mammotome or diagnostic surgical biopsy) and histology from needle core biopsy, mammotome biopsy and surgical biopsy.

Results

There were 35 needle core biopsies that contained pure FEA, of which 89% (31/35) were associated with mammographic calcification. Following initial core biopsy, 21 patients had further sampling with mammotome biopsy, 13 patients underwent diagnostic surgical biopsy and one patient was not suitable for further intervention. There was an upgrade to DCIS in 18% (6/34) and invasive carcinoma in 3% (1/34).

Conclusions

Pure FEA on core biopsy is upgraded to carcinoma in 21% (7/34) of cases on further sampling and it is vital that we do not underestimate the biological significance of FEA. Increasing the awareness of FEA is crucial to ensure consistent and appropriate patient management.