title: Interpretive disparity among pathologists in breast sentinel lymph node evaluation.
abstract: BACKGROUND
  Immunohistochemical staining on breast sentinel lymph nodes (SLN) is controversial.
  
  
  METHODS
  Twenty-five SLN cases were reviewed by 10 pathologists (three academic, seven private) including 5 negative by both hematoxylin and eosin (H&E) and immunohistochemistry, 11 micrometastases (<2 mm) negative by H&E but positive by immunohistochemistry, and 8 micrometastases and 1 macrometastasis (>2 mm) positive for both H&E and immunohistochemistry. Answers included "positive," "negative," and "indeterminate" for each slide.
  
  
  RESULTS
  The mean number of incorrect responses was 6.6 for immunohistochemistry and 5 for H&E. Twelve percent of cases were correct by all 10 pathologists; 80% of positive IHC cases had at least one pathologist score it incorrectly. As tumor cells decrease in number, incorrect responses increase. When tumor cells numbered less than 10, more than 30% of pathologists answered incorrectly.
  
  
  CONCLUSIONS
  As tumor cells decrease in number pathologists' ability to recognize them decreases. We propose adding "indeterminate" to "positive" and "negative" when tumor cells number less than 10.
authors.affiliation: Department of Pathology, St Paul University Hospital and University of Texas Southwestern Medical Center, Dallas, TX, USA. croberts@propathlab.com
authors.forename: Cory A
authors.initials: CA
authors.lastname: Roberts
authors.forename: Peter D
authors.initials: PD
authors.lastname: Beitsch
authors.forename: Craig E
authors.initials: CE
authors.lastname: Litz
authors.forename: D Sue
authors.initials: DS
authors.lastname: Hilton
authors.forename: Gene E
authors.initials: GE
authors.lastname: Ewing
authors.forename: Edward
authors.initials: E
authors.lastname: Clifford
authors.forename: Walton
authors.initials: W
authors.lastname: Taylor
authors.forename: Marc R
authors.initials: MR
authors.lastname: Hapke
authors.forename: Armineh
authors.initials: A
authors.lastname: Babaian
authors.forename: Imrana
authors.initials: I
authors.lastname: Khalid
authors.forename: Joe D
authors.initials: JD
authors.lastname: Hall
authors.forename: Guy
authors.initials: G
authors.lastname: Lindberg
authors.forename: Kyle
authors.initials: K
authors.lastname: Molberg
authors.forename: Hossein
authors.initials: H
authors.lastname: Saboorian
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D004396:Coloring Agents; D003951:Diagnostic Errors; D004801:Eosine Yellowish-(YS); D005260:Female; D006416:Hematoxylin; D006651:Histocytochemistry; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis / Q000175:diagnosis; D015588:Observer Variation; D010338:Pathology, Clinical; D015203:Reproducibility of Results; D021701:Sentinel Lymph Node Biopsy
chemical_list: D004396:Coloring Agents; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin