title: Assessing invasion criteria in fine needle aspirates from breast carcinoma diagnosed as DICS or invasive carcinoma: can we identify an invasive component in addition to DCIS?
abstract: OBJECTIVE
  To evaluate invasion criteria in fine needle aspiration cytology (FNAC) of histologically diagnosed breast ductal carcinoma in situ (DCIS) and invasive carcinoma and to evaluate their usefulness in identifying an invasive component in addition to DCIS.
  
  
  METHODS
  The material consisted of 331 smears diagnosed as suspicious for or consistent with DCIS and in which histology had shown either DCIS or invasive ductal carcinoma. All smears were reevaluated for the following invasion criteria: invasion of fat or fibrous tissue fragments, fibroblast proliferation, cell-poor elastoid tissue fragments, tubular structures and intracytoplasmic vacuoles.
  
  
  RESULTS
  All invasion criteria except cytoplasmic vacuoles correlated with invasiveness, but none of them were found exclusively in invasive lesions. Pseudoinvasion in fibrous or fatty tissue fragments were found in 8 cases of histologic pure DCIS. One DCIS (0.4%) revealed > or = 2 invasion features as well as 22 invasive carcinomas (20.7%), representing 7.4% of all cases.
  
  
  CONCLUSIONS
  Using established invasion criteria, practically no pure DCIS lesion will be diagnosed as invasive on FNAC, but one will identify only a subset of cases harboring an invasive component.
authors.affiliation: Department of Pathology, Faculty Division, Ullevaal University Hospital, University of Oslo, Norway. torill.sauer@medisin.uio.no
authors.forename: Torill
authors.initials: T
authors.lastname: Sauer
authors.forename: Oystein
authors.initials: O
authors.lastname: Garred
authors.forename: Jon
authors.initials: J
authors.lastname: Lømo
authors.forename: Oddvar
authors.initials: O
authors.lastname: Naess
mesh_terms: D044963:Biopsy, Fine-Needle; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology*; D005260:Female; D006801:Humans; D009361:Neoplasm Invasiveness / Q000473:pathology*