Review of diagnostic error in anatomical pathology and the role and value of second opinions in error prevention

Aims Diagnostic/interpretative accuracy can be challenging in anatomical pathology due to the subjective element of the diagnostic process. This can lead to false-negative or false-positive diagnoses of malignancy, variations in grading and diagnostic misclassification of a condition. It is imperative that an accurate diagnosis is achieved so that an appropriate and timely treatment is administered to the patient, for example, the success of targeted molecular therapeutic options for treatment of cancer is dependent on accurate anatomical pathology diagnoses being issued. Methods A literature review of diagnostic accuracy in selected specimen categories was undertaken and was compared with data on metropolitan and regional pathologist diagnostic proficiency performance in an external quality assurance programme from surveys provided 2015–2017. For each specimen category, cases having attracted a diagnostic inaccuracy (ie, major discordance) of ≥20% and cases attracting a combined error rate (ie, major and minor discordance) of ≥30% are reviewed and discussed. Results The rate of inaccurate diagnoses (assessed as a major discordance) ranged from 3% to 9% among the different specimen groups, with highest mean percentage of inaccurate diagnoses in gynaecology, dermatopathology and gastrointestinal specimens. Conclusions It was possible to ascertain that gynaecology, dermatopathology and gastrointestinal specimens had presented the greatest diagnostic challenge to the participant pathologists, determined as highest rate of diagnostic inaccuracy, that is, major discordance with respective case target diagnoses. Through a combination of routine second opinions, directed retrospective peer review and participation in appropriate external quality assurance schemes, the risk associated with these diagnoses can be minimised.