Prognostic significance of tumor budding, poorly differentiated cluster, and desmoplastic reaction in endometrioid endometrial carcinomas

Aims The tumor budding (TB); poorly differentiated cluster (PDC); desmoplastic reaction (DR); and microcystic, elongated, and fragmented (MELF) patterns of invasion are pathological findings at the tumor invasion front associated with epithelial‐to‐mesenchymal transition. This study aimed to clarify the clinical significance of the TB, PDC, DR, and MELF patterns in endometrioid endometrial carcinomas (EEC). Methods Two hundred and eight cases of histologically proven EEC retrieved from the archives of the Department of Pathology, Fukui Prefectural Hospital, and diagnosed between January 2000 and August 2020 were retrospectively analyzed. Results The TB, PDC, DR, and MELF patterns were identified in 29 (13.9%), 47 (22.6%), 45 (21.6%), and 23 (11.1%) cases, respectively. Kaplan–Meier curve analysis with log‐rank test demonstrated that TB, PDC, and DR were associated with a lower progression‐free survival (p = 0.010, 0.002, and