title: CD10 Immunohistochemical Expression in Apocrine Lesions of the Breast.
abstract: OBJECTIVE
  In the breast, CD10 is expressed by myoepithelial cells (MECs), and apocrine metaplasia has also been mentioned as being positive with this marker. Apocrine lesions have been explored for the expression of CD10.
  
  
  METHODS
  The apocrine lesions studied included 11 cysts, 6 cases of apocrine adenosis, 2 of apocrine metaplasia or hyperplasia in papilloma, 13 ductal carcinomas in situ (DCIS) and invasive carcinomas (14 ductal and 4 lobular).
  
  
  RESULTS
  Benign apocrine lesions showed complete or partial luminal CD10 staining, although most cases included parts without staining, and 2 lesions were completely negative. The MECs were often but not always positive. Nine of the 13 cases of apocrine DCIS displayed no luminal staining, but 4 demonstrated very focal luminal positivity. The MECs around the DCIS showed a spectrum of staining from nil to strong and complete. Only 4 invasive carcinomas demonstrated luminal/membranous staining. Cytoplasmic CD10 positivity was seen focally in 4 invasive cancers and in 3 DCIS.
  
  
  CONCLUSIONS
  CD10 positivity is luminal/membranous in most benign apocrine lesions, the staining being nonuniversal and sometimes focal. Analogous staining in apocrine malignancies seems rarer in DCIS and even rarer in invasive apocrine carcinomas, but atypical cytoplasmic positivity may also occur. CD10 is not an ideal myoepithelial marker in apocrine lesions.
authors.affiliation: Department of Pathology, University of Szeged, Szeged, Hungary.
authors.forename: Bence
authors.initials: B
authors.lastname: Kővári
authors.forename: Ágnes
authors.initials: Á
authors.lastname: Báthori
authors.forename: Gábor
authors.initials: G
authors.lastname: Cserni
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000276:immunology* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000276:immunology / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D005348:Fibrocystic Breast Disease / Q000276:immunology / Q000473:pathology; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D008679:Metaplasia; D015260:Neprilysin / Q000032:analysis*; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor; D015260:Neprilysin