十二指腸非腫瘍性ポリープの病理所見

Pathological Characteristics of Non-neoplastic Duodenal Polyps

要旨●十二指腸における非腫瘍性（腫瘍様）病変とされるポリープの病理学的特徴を概説する．腫瘍様病変には病理総論的に過誤腫あるいは分離腫とされる病変と，炎症性，再生性・過形成性に生じる病変がある．十二指腸は，空腸以下の小腸と異なり，特に近位側には粘膜下組織〜粘膜固有層内に胃幽門腺に似たBrunner腺と言われる粘液腺が発達し，胃型の細胞（腺窩上皮や胃底腺）が高頻度に出現する．十二指腸非腫瘍性ポリープを，胃型・Brunner腺型病変，小腸型病変，異所性膵（adenomyoma/myoepithelial hamartoma）と間葉系病変に分類して紹介したい．

　We outline the pathological characteristics of polyps that are considered to be non-neoplastic（tumor-like）lesions in the duodenum. Tumor-like lesions include lesions generally considered to be hamartomas or choristomas and lesions associated with inflammatory, regenerative, or hyperplastic changes. Unlike the small intestine below the jejunum, the duodenum develops mucous glands called Brunner glands that resemble gastric pyloric glands in the submucosal layer to the lamina propria, especially on the proximal side ; gastric-type cells（foveolar epithelium and fundic glands）appear frequently. Non-neoplastic duodenal polyps are introduced by classifying them into gastric/Brunner gland type, small intestinal type, ectopic pancreas（adenomyoma/myoepithelial hamartoma）, and mesenchymal lesions.