title: Interobserver variability by pathologists in the distinction between cellular fibroadenomas and phyllodes tumors.
abstract: Fibroepithelial lesions with cellular stroma are frequently termed cellular fibroadenomas although criteria for distinguishing them from a phyllodes tumor are vague and subjective. However, the clinical implications and surgical management for these 2 lesions may be different. We randomly selected 21 cases of fibroepithelial lesions sent in consultation to the senior author that were challenging to classify as cellular fibroadenoma or phyllodes tumor. One to 2 representative slides of each case along with patient age were sent to 10 pathologists who specialize in breast pathology. The World Health Organization criteria for phyllodes tumors and a diagnosis form were included with the study set. For the purposes of data reporting, fibroadenoma and cellular fibroadenoma are considered together. In only 2 cases was there uniform agreement as to whether the tumor represented a fibroadenoma or phyllodes tumor. Of the remaining 19 cases, if the diagnoses of fibroadenoma and benign phyllodes tumor were combined and separated from borderline and malignant phyllodes tumors, there was 100% agreement in 53% of cases and 90% agreement in 79% of cases. This study highlights the difficulty that exists in distinguishing some cellular fibroadenomas from phyllodes tumors even for pathologists who specialize in breast pathology. However, there appears to be considerable agreement when cellular fibroadenomas and benign phyllodes tumors are distinguished from borderline and malignant phyllodes tumors. Further studies are needed to determine if there is a clinically significant difference between cellular fibroadenomas and benign phyllodes tumors and how to better distinguish them from borderline and malignant phyllodes tumors.
authors.affiliation: University of North Carolina at Chapel Hill, Chapel Hill, NC, USA thomaslawton@mac.com.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Lawton
authors.affiliation: Ruffolo Hooper & Associates, Tampa, FL, USA.
authors.forename: Geza
authors.initials: G
authors.lastname: Acs
authors.affiliation: Johns Hopkins University Medical Center, Baltimore, MD, USA.
authors.forename: Pedram
authors.initials: P
authors.lastname: Argani
authors.affiliation: SA Pathology, Adelaide, South Australia, Australia Adelaide University, Adelaide, South Australia, Australia.
authors.forename: Gelareh
authors.initials: G
authors.lastname: Farshid
authors.affiliation: MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Gilcrease
authors.affiliation: Clarient, Inc, Aliso Viejo, CA, USA.
authors.forename: Neal
authors.initials: N
authors.lastname: Goldstein
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Frederick
authors.initials: F
authors.lastname: Koerner
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA.
authors.forename: J Jordi
authors.initials: JJ
authors.lastname: Rowe
authors.affiliation: Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Melinda
authors.initials: M
authors.lastname: Sanders
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Sejal S
authors.initials: SS
authors.lastname: Shah
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Reynolds
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D018226:Fibroadenoma / Q000473:pathology*; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D003557:Phyllodes Tumor / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult
keywords: cellular fibroadenoma; fibroepithelial lesion; phyllodes tumor