biostudies-literatureUnknown487(1)Mansour YAlma Mater Studiorum - Università di BolognaWith the reclassification of non-invasive follicular variant of papillary thyroid carcinoma as "tumors" (NIFTP), the challenge of diagnosing carcinoma lies in recognizing invasion: blood vessel invasion (BVI) or capsular invasion (CI). We aimed to assess reproducibility in diagnosing BVI and CI in follicular-patterned tumors using a web-platform, under conditions as close as possible to routine surgical pathology practice. Six-hundred-fourteen pathologists reviewed 69 thyroid lesions diagnostically challenging for BVI or CI, made available in three rounds: before, immediately after, and three months after a training lecture given by an expert pathologist. Each lesion was associated with a quiz (five queries: certain CI, doubtful CI, certain BVI, doubtful BVI, or no invasion). IntraobserverVirchows Archiv : an international journal of pathology105-116https://www.ebi.ac.uk/biostudies/studies/S-EPMC12289735biostudies-literatureCan we improve the diagnosis of invasion in encapsulated follicular-patterned thyroid tumors? Data from a massive international e-learning initiative.PMC12289735Cavillon ABelleannee GAl Bouzidi ASobrinho-Simoes MDe Leo AMansour YMrad KTallini GRamiandrasoa ALVibert NVielh PChaltiel LKamate BfalseCan we improve the diagnosis of invasion in encapsulated follicular-patterned thyroid tumors? Data from a massive international e-learning initiative.With the reclassification of non-invasive follicular variant of papillary thyroid carcinoma as "tumors" (NIFTP), the challenge of diagnosing carcinoma lies in recognizing invasion: blood vessel invasion (BVI) or capsular invasion (CI). We aimed to assess reproducibility in diagnosing BVI and CI in follicular-patterned tumors using a web-platform, under conditions as close as possible to routine surgical pathology practice. Six-hundred-fourteen pathologists reviewed 69 thyroid lesions diagnostically challenging for BVI or CI, made available in three rounds: before, immediately after, and three months after a training lecture given by an expert pathologist. Each lesion was associated with a quiz (five queries: certain CI, doubtful CI, certain BVI, doubtful BVI, or no invasion). Intraobserver2025-01-01T00:00:00Z2025 Jul2026-03-17T13:41:10.97Z2025-08-16T03:05:20.574ZS-EPMC122897353999243910.1007/s00428-025-04045-1