title: Diagnostic Discrepancies in Mandatory Slide Review of Extradepartmental Head and Neck Cases: Experience at a Large Academic Center.
abstract: BACKGROUND
  Medical error is a significant problem in the United States, and pathologic diagnoses are a significant source of errors. Prior studies have shown that second-opinion pathology review results in clinically major diagnosis changes in approximately 0.6% to 5.8% of patients. The few studies specifically on head and neck pathology have suggested rates of changed diagnoses that are even higher. Objectives .- To evaluate the diagnostic discrepancy rates in patients referred to our institution, where all such cases are reviewed by a head and neck subspecialty service, and to identify specific areas with more susceptibility to errors.
  
  
  METHODS
  Five hundred consecutive, scanned head and neck pathology reports from patients referred to our institution were compared for discrepancies between the outside and in-house diagnoses. Major discrepancies were defined as those resulting in a significant change in patient clinical management and/or prognosis.
  
  
  RESULTS
  Major discrepancies occurred in 20 cases (4% overall). Informative follow-up material was available on 11 of the 20 patients (55.0%), among whom, the second opinion was supported in 11 of 11 cases (100%). Dysplasia versus invasive squamous cell carcinoma was the most common (7 of 20; 35%) area of discrepancy, and by anatomic subsite, the sinonasal tract (4 of 21; 19.0%) had the highest rate of discrepant diagnoses. Of the major discrepant diagnoses, 12 (12 of 20; 60%) involved a change from benign to malignant, one a change from malignant to benign (1 of 20; 5%), and 6 involved tumor classification (6 of 20; 30%).
  
  
  CONCLUSIONS
  Head and neck pathology is a relatively high-risk area, prone to erroneous diagnoses in a small fraction of patients. This study supports the importance of second-opinion review by subspecialized pathologists for the best care of patients.
authors.affiliation: From the Departments of Pathology and Immunology (Drs Mehrad, Chernock, El-Mofty, and Lewis), and Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St Louis, Missouri (Drs Chernock, El-Mofty, and Lewis). Dr Lewis is now with the Department of Pathology, Microbiology, and Immunology, and the Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Mitra
authors.initials: M
authors.lastname: Mehrad
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Chernock
authors.forename: Samir K
authors.initials: SK
authors.lastname: El-Mofty
authors.forename: James S
authors.initials: JS
authors.lastname: Lewis
mesh_terms: D000046:Academic Medical Centers; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D006257:Head / Q000473:pathology*; D006258:Head and Neck Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008923:Missouri; D009333:Neck / Q000473:pathology*; D010338:Pathology, Clinical; D011379:Prognosis; D012017:Referral and Consultation