Abstract P1-02-11: Flat epithelial atypia on breast core biopsy: Is excision warranted?
Authors: Calhoun BC , White RL , Flippo-Morton T , Sarantou T , Gromet M , Sobel A , Livasy CA 
Published: August 2014

Abstract
Columnar cell lesions of the breast are common findings in core biopsies for mammographically indeterminate calcifications. Atypical columnar cell lesions, also referred to as flat epithelial atypia (FEA), confer a mildly increased risk of subsequent carcinoma and are often co-localized with other patterns of atypia. The management of FEA diagnosed on core biopsy remains controversial with studies reporting carcinoma on excisional biopsy in 13 to 67% of cases. We report the frequency of carcinoma in excision specimens after a diagnosis of FEA on core biopsy over a nine year period at Carolinas Medical Center.
Cases were identified from our files for the period from January 2004 through October 2012. Core biopsies with FEA as the most “advanced” lesion were included. Exclusion criteria included another pattern of atypia, carcinoma in situ, or invasive carcinoma in ipsilateral core biopsies performed concurrently or within four months of the core biopsy with FEA alone. The pathology reports for excision specimens following a core biopsy with FEA alone were retrieved. For each core biopsy with pure FEA, the histologic and mammographic findings were correlated.
A total of 116 cases with a diagnosis of FEA on core biopsy were identified. Two (2) cases were ultrasound core biopsies, 1 was MRI-guided, and the remaining 113 cases were stereotactic core biopsies performed for calcifications. FEA was the most advanced lesion in 53 cases (46%), corresponding to 55 core biopsies. In the 63 cases with FEA and a more advanced lesion, 34 (29%) contained atypical ductal hyperplasia, 6 (5%) atypical lobular hyperplasia, 4 (3%) atypical ductal and lobular hyperplasia, 11 (10%) ductal carcinoma in situ, 2 (2%) lobular carcinoma in situ, and 6 (5%) invasive carcinoma. Of the 55 core biopsies with FEA alone, excision pathology reports were unavailable for 11 cases, and an ipsilateral core biopsy contained a more advanced lesion in 6 cases. Of the 38 remaining cases, 4 excision specimens (11%) contained carcinoma and 8 specimens (21%) contained another, higher risk pattern of atypia (atypical ductal hyperplasia or atypical lobular hyperplasia). Excision results are summarized in the table below: 10 (26%) contained no residual atypia, 16 (42%) residual FEA, 7 (18%) atypical ductal hyperplasia, 1 (3%) atypical lobular hyperplasia, 3 (8%) ductal carcinoma in situ, and 1 (3%) invasive carcinoma.
Excision Findings after Pure FEA on Core BiopsyTotalNo AtypiaFEAADHALHDCISInvasive3810 (26%)16 (42%)7 (18%)1 (3%)3 (8%)1 (3%)
The data from a nine year period at our institution demonstrate an 11% upgrade rate to carcinoma for patients with a diagnosis of FEA on core biopsy. The higher risk patterns of atypia (atypical ductal hyperplasia or atypical lobular hyperplasia) found in 21% of cases also impact risk stratification and future clinical and radiographic follow-up. In total, future clinical management was altered in 32% of patients based on excision specimen results. The findings support performing an excisional biopsy for a core biopsy containing FEA.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-02-11.