Mandatory second opinion in cytopathology.

Background: Mandatory review of outside pathologic material is intended to detect interpretive errors that may have a clinically significant impact on patient care. Prior to definitive treatment of referred patients, the University of Iowa Carver College of Medicine requires a review of pertinent pathologic material previously obtained at outside institutions. The aims of this study were to determine if this local standard of practice has a measurable impact on patient care.

Methods: The pathologic diagnoses of 499 second opinion cytology cases seen at the University of Iowa Carver College of Medicine were studied. Each second opinion was classified as "no diagnostic disagreement", "minor disagreement", or "major disagreement" with respect to the originating institution's interpretation. The clinical impact of major disagreement cases was determined by pathologic and clinical follow-up via chart review.

Results: Second opinion cytology resulted in 37 cases (7.4% of total cases) with major diagnostic disagreements. Clinical and pathologic follow-up was available in 30 of the major disagreement cases; second opinion diagnosis was better supported in 22 of these cases compared to the outside diagnosis. The second opinion in 6 major disagreement cases prompted changes in clinical management.

Conclusions: Major disagreements in second opinion cytology are common, likely reflective of the challenges inherent in the interpretation of cytologic specimens. Although mandatory second opinion of outside cytologic material prompted changes in clinical management in only a small fraction of cases (1.2%), this rate was similar to those previously published for surgical pathology second opinion. These findings support the notion that mandatory second opinion policy as an important part of patient care.