| [ Summary ] |
Non-ampullary duodenal epithelial tumors (NADETs) are rare, but the number of resected specimens has been increasing in recent years, both in Japan and in other countries. Most cases of duodenal non-papillary tumors occur in the 1st-2nd portion, and the main macroscopic type is protuberant. Histologically, Brunner's glands arising from the duodenal bulb to the proximal descending duodenum are considered a gastric phenotype. Tumors arising from the duodenum present as intestinal type, gastric type, and gastrointestinal mixed type on immunohistochemical analysis. Herein, we propose a new pathological diagnostic algorithm based on related reports. The diagnostic criteria for low grade duodenal epithelial tumors are basically the same as those of gastric cancer, although the differential diagnosis can be difficult. As the clinicopathological features have not been elucidated due to the extremely low incidence, it is important to collect more cases for analysis. |