Inter-observer reproducibility in the diagnosis of gastric intraepithelial neoplasia in ESD specimens: A multi-center study in Korea

초록

Objectives Gastric intraepithelial neoplasia (IEN) comprises various cytological and architectural alterations, and the terminology and diagnostic criteria are controversial across the world. The purpose of this study was to investigate how many discrepancies occur in the pathologic diagnosis of IEN in endoscopic submucosal dissection (ESD) specimens, and to evaluate the reasons for discordance. Methods We retrospectively reviewed 1,202 ESD specimens that were originally diagnosed as gastric IEN at 12 institutions. Results The final consensus diagnosis, made by a team of expert gastrointestinal pathologists, was carcinoma in 756 cases, of which 692 (91.5%), 43 (5.7%), 20 (2.6%) and 1 (0.1%) cases were originally diagnosed as carcinoma, high-grade dysplasia, low-grade dysplasia and others, respectively. Final diagnoses of high- and low-grade dysplasia were made in 63 and 342 cases, respectively. The diagnostic accuracy was the highest for carcinoma (91.5%), followed by low-grade dysplasia (86.3%), others (63.4%) and high-grade dysplasia (50.8%). The general kappa value was 0.83, indicating excellent concordance. The kappa values of individual institutions ranged from 0.74 to 1 and correlated with the proportion of carcinoma cases. The cases revised to a final diagnosis of carcinoma exhibited both architectural abnormalities and cytologic atypia. The main differential points between low- and high-grade dysplasias were the glandular distribution and glandular shape. Additional features such as the glandular axis, surface maturation, nuclear stratification and nuclear polarity were also important. Associated inflammation, erosion, regeneration and focality of the lesions were pitfalls for the diagnosis of carcinoma and dysplasia. Conclusions The overall reproducibility of the diagnosis of gastric IEN was excellent.