Low accuracy and interobserver/intraobserver agreement for colorectal sessile serrated lesions: A multicenter diagnostic study

Figure 1 Pathomorphological features of different types of colorectal polyp lesions. A: Similar to normal crypt morphology, but primarily composed of goblet cells with small, uniform nuclei located at the base (goblet cell-rich hyperplastic polyp, hematoxylin-eosin, original magnification 100 ×); B: The surface of the crypts exhibits serrated architectures, with the cross-section displaying a star-like pattern, and small droplet-like mucus can be observed scattered within the epithelial cells (microvesicular hyperplastic polyp, hematoxylin-eosin, original magnification 40 ×); C: The serrated crypts are prominently displayed, extending deeply into the crypts with dilation and branching, giving the gland a distinctive ‘L’-shaped configuration (sessile serrated lesion, hematoxylin-eosin, original magnification 100 ×); D: Serrated or fissure-like crypts are observed, with the presence of ectopic crypts. The nuclei exhibit elongation resembling a pencil, and the cytoplasm displays significant eosinophilia (traditional serrated adenoma, hematoxylin-eosin, original magnification 100 ×); E: The glandular tissue exhibits an irregular tubular pattern with a crowded arrangement of cells and deeply stained nuclei (tubular adenoma, hematoxylin-eosin, original magnification 100 ×); F: The glandular tissue exhibits an irregular tubular and villous configuration, with cells demonstrating atypia and deeply stained nuclei (tubulovillous adenoma, hematoxylin-eosin, original magnification 100 ×).

Figure 2  Research process workflow.

Figure 3 Diagnostic accuracy and interobserver agreement by experience level. A: Diagnostic accuracy of different experience level and pathology subtype across reading rounds. Significance vs junior group: ^bP < 0.01, ^cP < 0.001; B: Interobserver agreement by experience level across reading rounds. Reference lines: κ = 0 (dashed), κ = 0.2/0.4 (dotted). ^aNegative values indicate agreement worse than chance. SSL: Sessile serrated lesion; SSL-D: Sessile serrated lesion with dysplasia.