Analysis of Clinical and Pathologic Factors of Pure, Flat Epithelial Atypia on Core Needle Biopsy to Aid in the Decision of Excision or Observation

Abstract

Background: The optimal treatment of flat epithelial atypia (FEA) found on breast core needle biopsy (CNB) is controversial. We performed a retrospective review of our institutional experience with FEA to determine if excisional biopsy may be deferred.

Methods: Surgical records from 2009 to 2012 were reviewed for FEA diagnosis. After exclusion for concomitant lesions, CNBs of pure FEA were classified using a previously agreed upon descriptor of "focal" versus "prominent". Data was analyzed with the Fisher's Exact and Student-t test as appropriate.

Results: Of 71 CNBs evaluated, pure FEA was identified on 27 CNBs. Final excisional biopsy was benign in 24 of 27 cases (88%) with associated ductal carcinoma in-situ (DCIS) in 3 of 27 cases (11%). Eighteen of 27 (67%) CNBs were classified as focal while 9 (33%) were described as prominent. Zero of the 18 focal patients had a malignancy compared to 3 of the 9 in the prominent group (0% vs 33%, p=0.02). Of the 27 pure FEA CNBs, 6 patients had a personal history of breast carcinoma, five DCIS and one invasive ductal carcinoma. No malignancies were found in the 21 patients without a personal history of breast carcinoma versus three in the patients with a positive history (0/21 v 3/6, p=0.007).

Conclusions: Our data suggests those women who have adequate sampling and sectioning of CNBs, with focal, pure FEA on pathology, and are without a personal history of breast cancer may undergo a period of imaging surveillance. Conversely, patients with a history of breast cancer or pure, prominent FEA on CNB disease should proceed to excisional biopsy.

Keywords: Columnar Cell Change with atypia; Columnar Cell Hyperplasia with Atypia.; DIN 1A; Ductal Intraepithelial Neoplasia; Pure FEA; Pure Flat Epithelial Atypia.

FIGURES 1

A-B Lowest end of Focal Flat Epithelial Atypia spectrum (at 10x and 20x magnification, respectively). Within this lobule, some acini exhibit round dilated acini with subtly enlarged and rounded nuclei with increased nuclear to cytoplasmic ratio (leading to basophilic appearance from hyperchromasia) and prominent nucleoli, and some nuclei no longer are oriented perpendicular to the acini's basement membrane (microscopic features of FEA). Secretions and microcalcifications are present within the some of the acinar lumina (which can be seen in FEA or non-involved acini). C Focal Flat Epithelial Atypia at 10x magnification, single lobule with the basophilic appearance characteristic of increased nuclear to cytoplasmic ratio and nuclear hyperchromasia; other nuclear atypia consisting of nucleoli and disorganized nuclear arrangement is visible along with occasional bi-nucleation. Some cells have apical snouts, a non-specific finding. D-E Prominent Flat Epithelial Atypia (10x magnification): Multiple lobules with enlarged, rounded or irregularly dilated acini, which exhibit basophilia due to increased nuclear to cytoplasmic ratio and nuclear hyperchromasia, are evident. Prominent Flat Epithelial Atypia (20x magnification): Monomorphic population of rounded and enlarged nuclei, not regularly oriented perpendicular to the basement membrane, with prominent nucleoli lining multiple lobules. Some acini contain microcalcifications and majority of cells exhibit apical snouts.

Figure 2

A total of 71 core needle biopsies (CNBs) with flat epithelial atypia (FEA) were reviewed. Sixty-two percent (n=44) were excluded for presence of a separate surgical indication or lack of adequate excisional biopsy (EB). Pure FEA core needle biopsies were designated as “focal” or “prominent”. The focal FEA group contained no malignancies on excisional biopsy, compared to 33% (n=3) in the prominent group (0% v. 33%, p=0.02).

Figure 3

Pure, Flat epithelial atypia was identified on 38% (27/71) of core needle biopsies (CNBs). Sixty-two percent of patients were excluded for a lack of an adequate excisional biopsy or the presence of a concomitant lesion; ductal carcinoma in-situ (DCIS), lobular carcinoma in-situ (LCIS), atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), phyllodes tumor, pseudoangiomatous stromal hyperplasia (PASH), or fibroadenoma.