title: Early (<10 mm) HER2-Positive Invasive Breast Carcinomas are Associated with Extensive Diffuse High-Grade DCIS: Implications for Preoperative Mapping, Extent of Surgical Intervention, and Disease-Free Survival.
abstract: BACKGROUND
  The few publications on <10-mm invasive breast carcinomas have reported worse outcomes for women with human epidermal growth factor receptor 2 (HER2)-positive cancer compared with HER2-negative cases and indicated that the high risk of recurrence in HER2-positive cases is related to the high grade, hormone receptor negativity, and high proliferation index of the invasive tumor component.
  
  
  METHODS
  We studied the subgross morphology of such tumors in a consecutive series of 203 cases documented in large-format histology slides and worked up with detailed radiological-pathological correlation.
  
  
  RESULTS
  The invasive component was associated with a diffuse in situ component in 78 % of the HER2-positive and 26 % of HER2-negative tumors <10 mm in size (odds ratio [OR], 11.3936; P < .0001). The in situ component was of high grade in 75 % of HER2-positive and 9 % of HER2-negative cases (OR, 29.6000; P < .0001). Significant associations were also found between the HER2 positivity of the invasive component and diffuse combined lesion distribution (P > .0001), invasive tumor grade 3 (P = .0004), presence of vascular invasion (P = .0026), extensive disease (P = .0170), "not special" (ductal) histological tumor type (P = .0302), estrogen receptor negativity (OR, 7.8846; P < .0001), and high Ki67 proliferation index (OR, 5.0000; P = .0007). The HER2-positive tumors tended to be multifocal (OR, 2.000) and lymph node-positive (OR, 3.0147), but the tendency was not statistically significant.
  
  
  CONCLUSIONS
  The vast majority of <10-mm HER2-positive breast carcinomas exhibited a high-grade, diffuse, and extensive in situ component, which may explain the high risk of recurrence among these tumors.
authors.affiliation: Department of Pathology and Clinical Cytology, Central Hospital Falun, Falun, Sweden, tibor.tot@ltdalarna.se.
authors.forename: Tibor
authors.initials: T
authors.lastname: Tot
mesh_terms: D001808:Blood Vessels / Q000473:pathology; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry* / Q000473:pathology* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008940:Mitotic Index; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D011300:Preoperative Care; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis; D047368:Tumor Burden
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; C508053:ERBB2 protein, human