title: Pseudoangiomatous Stromal Hyperplasia in Core Needle Biopsies of Breast Specimens.
abstract: BACKGROUND
  Pseudoangiomatous stromal hyperplasia (PASH) is a benign lesion of myofibroblasts that is composed of a network of slit-like channels that resemble vascular spaces. The aims of this study were to document the frequency of PASH in core needle biopsy specimens (CNBS) of the breast, to describe which histopathologic findings coexist with PASH and to examine any endothelial cell differentiation.
  
  
  METHODS
  We reevaluated hematoxylin and eosin-stained sections of all CNBS that were obtained during a 1-year period. First, we performed CD34 and CD31 immunostainings to highlight the areas of PASH, then performed D2-40/podoplanin (lymphatic endothelial marker) and Fli-1 (vascular endothelial cell marker) immunostains.
  
  
  RESULTS
  The total number of CNBS was 412. Areas of PASH were noted in 37 of the 412 cases (9%), with a mean age of 38.5 years. The lesions that were described in association with PASH were "benign breast parenchyma with stromal fibrosis" (17/37; 46%), "fibroepithelial tumors" (17/37; 46%), "columnar cell changes (CCC)" (2/37; 5%), and "invasive carcinoma" (1/37; 3%). There were 2 cases of CCC within the foci of PASH (direct contact with PASH), and 8 additional cases of CCC that coexisted in the same specimen but were not in direct contact. There was no staining for D2-40 or Fli-1 within PASH foci.
  
  
  CONCLUSIONS
  PASH lesions occurred with a frequency of 9% in CNBS and were mostly in association with benign breast lesions in premenopausal women. CCC was determined as an accompanying epithelial lesion within or near PASH areas. No obvious immunopositivity compatible with endothelial cell differentiation was revealed.
authors.affiliation: 1 Istanbul Research and Training Hospital, Pathology Department, Fatih, Istanbul, Turkey.
authors.forename: Canan
authors.initials: C
authors.lastname: Kelten Talu
authors.affiliation: 1 Istanbul Research and Training Hospital, Pathology Department, Fatih, Istanbul, Turkey.
authors.forename: Ceren
authors.initials: C
authors.lastname: Boyaci
authors.affiliation: 1 Istanbul Research and Training Hospital, Pathology Department, Fatih, Istanbul, Turkey.
authors.forename: Cem
authors.initials: C
authors.lastname: Leblebici
authors.affiliation: 1 Istanbul Research and Training Hospital, Pathology Department, Fatih, Istanbul, Turkey.
authors.forename: Ezgi
authors.initials: E
authors.lastname: Hacihasanoglu
authors.affiliation: 1 Istanbul Research and Training Hospital, Pathology Department, Fatih, Istanbul, Turkey.
authors.forename: Erol Rustu
authors.initials: ER
authors.lastname: Bozkurt
mesh_terms: D000293:Adolescent; D000328:Adult; D000798:Angiomatosis / Q000473:pathology*; D015415:Biomarkers / Q000032:analysis; D062005:Biopsy, Large-Core Needle; D001941:Breast Diseases / Q000473:pathology*; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000473:pathology*; D007150:Immunohistochemistry; D008875:Middle Aged; D012189:Retrospective Studies; D017154:Stromal Cells / Q000473:pathology; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: D2-40; Fli-1; PASH; breast; pseudoangiomatous stromal hyperplasia