title: Can problematic fibroepithelial lesions be accurately classified on core needle biopsies?
abstract: Fibroepithelial lesions (FEL) of the breast are notoriously difficult to classify on core needle biopsies. The goal of this study was to evaluate interobserver variability and accuracy of subclassifying difficult FELs into fibroadenoma (FA) and phyllodes tumors (PTs). We identified 50 breast core needle biopsies, initially diagnosed generically as FEL, with subsequent excision and final diagnosis of either FA or benign PT. Five surgical pathologists from one institution independently reviewed these in 3 rounds. The pathologists were blinded to the final excisional diagnosis. Two diagnostic categories were allowed: FA and PT. A set of histologic criteria was provided including the presence of subepithelial condensation, stromal heterogeneity, overgrowth, pleomorphism, fragmentation, cellularity, adipose tissue entrapment, and mitotic count and asked to review the slides for the second round. A third round of interpretations was conducted after each criterion was defined. Interobserver agreement for the diagnosis and each criterion was evaluated using the κ level of agreement. Accuracy of ratings to final diagnosis was calculated using Wilcoxon signed-rank test. κ Values for interobserver agreement were fair for the first and second rounds varying from 0.20 to 0.22, respectively. This increased to 0.27 in round 3. When considering each category, the κ value varied from 0.26 to 0.29 for FA and 0.28 to 0.14 for PT. Overall, there was fair agreement between the pathologists in all categories. The rate of correctly diagnosed cases ranged from 40% in the first round, to 48% in the second round, to 67% in round 3. Overall the pathologists performed better in identifying FA than PT. The accuracy of interpretations was significantly different between the first (40%), second (48%), and third rounds (67%).
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Sudeshna
authors.initials: S
authors.lastname: Bandyopadhyay
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Barak
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Kinda
authors.initials: K
authors.lastname: Hayek
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Sumi
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Haleema
authors.initials: H
authors.lastname: Saeed
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Rafic
authors.initials: R
authors.lastname: Beydoun
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Dongping
authors.initials: D
authors.lastname: Shi
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Haitham
authors.initials: H
authors.lastname: Arabi
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201.
authors.forename: Julie
authors.initials: J
authors.lastname: Ruterbusch
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201; Karmanos Cancer Institute, Population Studies and Disparities Research Program, Detroit, MI 48201.
authors.forename: Michele
authors.initials: M
authors.lastname: Cote
authors.affiliation: Department of Pathology, Wayne State University, Detroit, MI 48201. Electronic address: rali@med.wayne.edu.
authors.forename: Rouba
authors.initials: R
authors.lastname: Ali-Fehmi
mesh_terms: D000328:Adult; D000368:Aged; D062005:Biopsy, Large-Core Needle; D001943:Breast Neoplasms / Q000145:classification / Q000473:pathology*; D005260:Female; D018226:Fibroadenoma / Q000145:classification / Q000473:pathology*; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D003557:Phyllodes Tumor / Q000145:classification / Q000473:pathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Concordance; Core biopsy; Fibroepithelial lesions; Inter-observer variability; Phyllodes tumor