Abstract and Introduction
Abstract
Objectives: To establish baseline error rates due to misinterpretation and to identify scenarios in which major errors were most common and potentially preventable.
Methods: Our database was queried over a 3-year period for major discrepancies due to misinterpretation. These were stratified by histomorphologic setting, service, availability/type of prior material, and years of experience and subspecialization of the interpreting pathologist.
Results: The overall discordance rate between frozen section (FS) and final diagnoses was 2.9% (199/6,910). Seventy-two errors were due to interpretation, of which 34 (47.2%) were major. Major error rates were highest on the gastrointestinal and thoracic services. Of major discrepancies, 82.4% were rendered in subdisciplines outside those of the FS pathologist. Pathologists with fewer than 10 years' experience made more errors than those with more experience (55.9% vs 23.5%, P = .006). Major error rates were greater for cases without previous material compared to those with a prior glass slide (47.1% vs 17.6%, P = .009). Common histomorphologic scenarios in which disagreements were made involved discriminating mesothelial cells from carcinoma (20.6%) and accurately recognizing squamous carcinoma/severe dysplasia (17.6%).
Conclusions: To improve performance and decrease future misdiagnoses, monitoring discordances should be a continuous component of surgical pathology quality assurance programs.
Introduction
Intraoperative frozen section (FS) analysis is a valuable tool that guides surgical management at the operating table. It has long been effective in identifying unknown tissue, determining the extent of disease, assessing margin status, and ascertaining tumor type. Accurate interpretation may be challenging. It requires not only recognition of pathologic entities and their mimics but also correlation with the clinic-laboratory and radiologic findings, knowledge of procedural limitations, and clear communication with the surgery teams. Awareness of factors that may contribute to discrepancies between the rapid intraoperative assessment and those made upon review of the permanent section can also help to improve the overall diagnostic outcome.
Errors in FS diagnosis can be categorized as due to inadequate sampling or interpretation. The former occurs when the levels of tissue examined during FS contain no lesion, but the permanent section performed later on the remaining tissue does. Interpretation error arises in 1 of 2 scenarios: either the lesion is evident on the FS but is not recognized by the pathology, or it is "called" incorrectly. The second and less frequent situation is when no lesion is present but the pathologist diagnoses it as present.
Correlation of the FS diagnosis with the final pathologic diagnosis is an important part of quality assurance in surgical pathology. Published discrepancy rates average around 1% to 4%, with approximately 30% to 60% attributable to misinterpretation of the original FS.[1–5] To date, there is limited literature on the precise nature of these errors. The goals of this study were to establish baseline data error rates due to misinterpretation at a large academic institution and to identify specific scenarios in which major errors were most common and potentially preventable.
Am J Clin Pathol. 2023;160(3):247-254. © 2023 American Society for Clinical Pathology
