title: Breast MRI-detected cystic apocrine metaplasia: imaging features with microvessel analysis and histologic correlation.
abstract: OBJECTIVE
  The purpose of this article is to characterize the histologic vascular features and distinguishing MRI features of cystic apocrine metaplasia to better understand imaging-pathology concordance.
  
  
  METHODS
  Retrospective review of 261 consecutive MRI-guided biopsy cases was performed. Pathology results were reviewed for all biopsies; cystic apocrine metaplasia was identified as the predominant finding in 19 cases (7%). CD31 immunohistochemistry was subsequently performed on the most representative block of cystic apocrine metaplasia, and microvasculature was evaluated using computer-assisted image analysis. The contrast-enhanced MRI examinations correlating with the cystic apocrine metaplasia cases were independently reviewed by two radiologists specializing in breast imaging; lesions were analyzed for morphologic, kinetic, and T2 characteristics.
  
  
  RESULTS
  On MRI review, 17 of 19 (89%) lesions were 10 mm or smaller. Washout kinetics were present in 11 of 19 (58%) lesions, and 14 of 19 (74%) lesions were at least partially hyperintense on T2-weighted sequences relative to adjacent glandular tissue. Cystic apocrine metaplasia had a higher percentage area (mean, 4.1%) of CD31-immunostained microvessels compared with background fibroglandular tissue (mean, 1.2%).
  
  
  CONCLUSIONS
  Cystic apocrine metaplasia should be considered in the differential diagnosis of a T2-hyperintense enhancing focus or subcentimeter smoothly marginated mass, even if associated with washout kinetics. Cystic apocrine metaplasia contains a statistically significant increase in microvessel area compared with background fibroglandular tissue and fat and, therefore, may be considered a concordant result for this set of imaging findings.
authors.affiliation: 1 Department of Radiology, Dartmouth-Hitchcock Medical Center, 1 Medical Center Dr, Lebanon, NH 03756.
authors.forename: Roberta M
authors.initials: RM
authors.lastname: diFlorio-Alexander
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Marotti
authors.forename: Jesse S
authors.initials: JS
authors.lastname: Bond
authors.forename: Mary C
authors.initials: MC
authors.lastname: Schwab
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Memoli
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Wells
authors.forename: Steven P
authors.initials: SP
authors.lastname: Poplack
mesh_terms: D000328:Adult; D000368:Aged; D001050:Apocrine Glands / Q000473:pathology*; D001940:Breast / Q000098:blood supply* / Q000473:pathology*; D005260:Female; D005348:Fibrocystic Breast Disease / Q000473:pathology*; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008679:Metaplasia / Q000473:pathology; D055806:Microvessels / Q000473:pathology*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
keywords: MRI; breast; cystic apocrine metaplasia