title: Misclassification of bronchioloalveolar carcinoma with cytologic diagnosis of lung cancer.
abstract: BACKGROUND
  Cytology is commonly used to diagnose non-small cell lung cancer (NSCLC) but is an inaccurate means of diagnosis of bronchioloalveolar carcinoma (BAC). The aims of this study were to calculate the sensitivity and specificity of cytologic diagnosis of BAC and to estimate the misclassification of BAC as other subtypes of NSCLC.
  
  
  METHODS
  Preoperative fine-needle aspiration cytology diagnoses were compared to histology diagnoses in 222 patients, including 51 patients with pure or mixed BAC, who underwent lung resection for NSCLC at our institution since 1999.
  
  
  RESULTS
  The sensitivity and specificity of a cytologic diagnosis of BAC were 12% and 99%, respectively. Based on cytologic diagnosis, 63% of BAC was misclassified as adenocarcinoma, and 18% was misclassified as undifferentiated NSCLC. In this cohort, 35% of adenocarcinomas and 12% of undifferentiated NSCLC diagnosed by cytology had BAC histology.
  
  
  CONCLUSIONS
  Diagnosis of NSCLC by cytology alone results in significant misclassification of BAC, most commonly as adenocarcinoma or undifferentiated NSCLC. Because patients with BAC respond differently to certain treatments such as endothelial growth factor receptor inhibitors and surgical resection of multifocal lung cancer, misclassification of BAC may have important therapeutic implications.
authors.affiliation: Department of Surgery, Division of Cardiothoracic Surgery and the UCSF Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94131, USA. Dan.raz@ucsf.edu
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Raz
authors.forename: Jason A
authors.initials: JA
authors.lastname: Zell
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Karnezis
authors.forename: Anobel
authors.initials: A
authors.lastname: Odisho
authors.forename: S H
authors.initials: SH
authors.lastname: Ignatius Ou
authors.forename: Hoda
authors.initials: H
authors.lastname: Anton-Culver
authors.forename: David M
authors.initials: DM
authors.lastname: Jablons
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D003581:Cytodiagnosis / Q000145:classification; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity