Real-World Data of Comprehensive Genomic Profiles and Clinicopathological Characteristics of Duodenal Epithelial Neoplasms

Background/Objectives: Duodenal epithelial neoplasms are rare; however, the widespread use of surveillance endoscopy and advances in endoscopic imaging technology have increased their incidental detection. Owing to their rarity, the clinicopathological characteristics and natural course of duodenal epithelial neoplasms have not been thoroughly investigated. In this study, we aimed to clarify the genomic profile and clinicopathological characteristics of duodenal epithelial neoplasms. Methods: A total of 158 patients with duodenal epithelial neoplasms were enrolled. Comprehensive genomic profiling and immunohistochemical staining were performed. Immunophenotypes were categorized as gastric type (G-type), gastrointestinal type (GI-type), or intestinal type (I-type). The detection rate of potentially actionable genomic alterations and a high tumor mutational burden (TMB-H ≥ 10 Muts/Mb) were evaluated and compared across tumor types. Results: The median size of adenocarcinomas was larger than that of adenomas (p = 0.002). The age at diagnosis of G-type tumors was higher than that for the other two tumor types (p < 0.001). The median size of I-type tumors was smaller than that of the other two tumor types (p = 0.019). Compared with the other two types, G-type tumors were predominantly located in the superior region (p < 0.001), were macroscopic Type I (p = 0.002), and had significantly higher genomic alteration rates for KRAS (p < 0.001), GNAS (p < 0.001), CDKN2A (p = 0.004), and MDM2 (p < 0.001). Eighteen patients showed TMB-H. Conclusions: TMB-H was observed in >10% duodenal tumors. Additionally, the pathogenesis of G-type duodenal tumors differs from that of other immunophenotypic tumors. These findings could help in understanding the genomic profiles of duodenal tumors and in selecting treatment options.