de novo発生と思われる十二指腸低異型度（高分化）管状腺癌の1例

Apparent de novo Development of a Duodenal Low-grade Well-differentiated Adenocarcinoma, Report of a Case

要旨●患者は70歳代，女性．嘔気を主訴として当院消化器内科を受診した．MRIにて上十二指腸角付近に狭窄を，FDG-PET/CTにて同部位に限局性の壁肥厚を指摘された．上部消化管内視鏡検査で上十二指腸角付近にて狭窄を認めたものの，びらん部からの生検では悪性所見は指摘できなかった．診断的治療目的で施行された幽門側胃切除術中の術中迅速診断で高分化腺癌が指摘された．術後の病理組織標本にて低異型度高分化腺癌を認めた．免疫染色を施行したところ，腫瘍はMUC2とCD10に陽性，MUC5ACとMUC6は陰性で腸型の形質を示した．腫瘍の辺縁に腺腫成分は確認できず，de novoに発生した腫瘍と考えられた．

　We report the case of a woman in her 70s, who presented to the Department of Gastroenterology at our hospital with the chief complaint of nausea. MRI showed stenosis near the superior duodenal angle. FDG-PET showed localized wall thickening in the same area. Upper gastrointestinal endoscopy revealed stenosis near the supraduodenal angle ; however, a biopsy of the erosive area did not reveal evidence of malignancy on histological analysis. Distal gastrectomy was performed for diagnostic and therapeutic purposes, with histopathological examination of the resected specimen, which demonstrated well-differentiated adenocarcinoma with mild atypia. Immunohistochemical analysis was positive for MUC2 and CD10 and negative for MUC5AC and MUC6 indicating intestinal origin. No malignant characteristics were seen at tumor margins, which suggested de novo tumor development.