title: Flat epithelial atypia of the breast: pathological-radiological correlation.
abstract: OBJECTIVE
  This study was undertaken to determine the prevalence of flat epithelial atypia at ultrasound-guided and stereotactically guided needle biopsies, to describe the mammographic and sonographic features of flat epithelial atypia, and to determine the significance of lesions diagnosed as flat epithelial atypia at imaging-guided needle biopsies.
  
  
  METHODS
  Retrospective review of a database of 1369 consecutive sonographically and stereotactically guided needle biopsies performed during a 12-month period yielded 33 lesions with flat epithelial atypia as the most severe pathologic entity (32 patients). Two radiologists retrospectively reviewed the imaging presentation, by combined consensus, according to the BI-RADS lexicon.
  
  
  RESULTS
  Twenty-two of 33 flat epithelial atypia diagnoses (67%) were obtained under stereotactic guidance, and 11 (33%) were obtained under sonographic guidance. Six patients had synchronous breast cancer. Flat epithelial atypia lesions presented mammographically most often as microcalcifications (20/33 [61%]) distributed in a cluster (14/20 [70%]) with amorphous morphology (13/20 [65%]). Sonographically, flat epithelial atypia lesions appeared most often as masses (9/11 [82%]), with an irregular shape (6/9 [67%]), microlobulated margins (5/9 [56%]), and hypoechoic or complex echotexture (7/9 [78%]). Twenty-eight of 33 lesions (85%) were surgically excised, confirming the flat epithelial atypia diagnosis in 11 of the 28 lesions (39%), yielding carcinoma in four (14%) and atypical ductal hyperplasia in six (21%). Columnar cell changes without atypia were diagnosed in four lesions (14%), and lobular carcinoma in situ was diagnosed in three lesions (11%).
  
  
  CONCLUSIONS
  Mammographic and sonographic presentation of flat epithelial atypia is not specific (clustered amorphous microcalcifications and irregular, hypoechoic or complex masses). Given the underestimation rate of malignancy, surgical excision should be considered when imaging-guided biopsy yields flat epithelial atypia.
authors.affiliation: Cedar Breast Clinic, Department of Radiology, McGill University Health Center, Royal Victoria Hospital, 687 Pine Ave W, Montreal, PQ H3H 1A1, Canada.
authors.forename: Silma
authors.initials: S
authors.lastname: Solorzano
authors.forename: Benoît
authors.initials: B
authors.lastname: Mesurolle
authors.forename: Attila
authors.initials: A
authors.lastname: Omeroglu
authors.forename: Mona
authors.initials: M
authors.lastname: El Khoury
authors.forename: Ellen
authors.initials: E
authors.lastname: Kao
authors.forename: Ann
authors.initials: A
authors.lastname: Aldis
authors.forename: Sarkis
authors.initials: S
authors.lastname: Meterissian
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000379:methods*; D001941:Breast Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D011230:Precancerous Conditions / Q000000981:diagnostic imaging / Q000473:pathology*; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D018084:Ultrasonography, Interventional; D016217:Ultrasonography, Mammary