What is the significance of flat epithelial atypia and what are the management implications?

To assess the significance of flat epithelial atypia (FEA) on core biopsy by evaluating the proportion of cases upgraded to in-situ and invasive carcinoma on further sampling with vacuum-assisted biopsy (VAB) or diagnostic surgical biopsy.

A retrospective analysis was performed of all core biopsies containing FEA and/or atypical intraductal proliferation (AIDP) in the pathology database from April 2008 to April 2010 (n=90). Before April 2009, the majority of core biopsies containing FEA and/or AIDP proceeded to surgical biopsy. From April 2009 onwards, a new patient management pathway was introduced incorporating VAB to sample core biopsies containing FEA and/or AIDP as an alternative to surgical biopsy.

Of 90 core biopsies, the following were identified: FEA only in 42%; FEA with concomitant AIDP in 21% and AIDP only in 37%. There was a stepwise increase in the proportion of cases upgraded to in-situ or invasive carcinoma: 19% in the FEA group; 29% in the FEA and AIDP group and 53% in the AIDP group. In the FEA-only group, one invasive tumour (grade 1 tubular carcinoma) and six cases of ductal carcinoma in situ were found.

The presence of FEA on core biopsy warrants further tissue sampling to ensure concomitant malignancy is not missed. Sampling with VAB provides sufficient tissue for histopathological evaluation, reducing the need for surgical biopsy. It is important that the utilisation of VAB is incorporated into a safe patient management pathway with careful multidisciplinary team discussion to ensure radiological-pathological concordance.