外科的に切除した十二指腸neoplasm of uncertain malignant potential と考えられた 1 例

Reports of duodenal neoplasms have recently increased, possibly because of advances in endoscopic equipment and widespread treatment of Helicobacter pylori eradication. Hida et al. classified gastric-type duodenal neoplasms into “adenomas,”“invasive carcinomas,”and“borderline lesions: neoplasm of uncertain malignant potential (NUMP).” NUMP is a tumor comprising slightly atypical epithelial cells growing in a fused or anastomosing glandular pattern, often with expansive submucosal extension, without severe nuclear atypia or lymphatic or vascular invasion. Here, we report a case of NUMP treated with pancreaticoduodenectomy. A type 0 - I lesion with a submucosal bulge was noted in the duodenal bulb of a 73-year-old man during an upper gastrointestinal endoscopy. A biopsy of the lesion suggested a NUMP. However, because EUS showed submucosal invasion of the duodenum with a concomitant intraductal papillary mucinous tumor of the pancreas, he underwent pancreaticoduodenectomy and was finally diagnosed with NUMP. The treatment of NUMP has not yet been established, and an accumulation of such cases is needed.