十二指腸粘膜の特異性と小病変の病理―特に腫瘍および腫瘍様病変について

Specificity of Duodenal Mucosa, and Small Tumors and Tumor-like Lesions of the Duodenum

要旨　十二指腸の解剖学的・組織学的特徴と該部にみられる小病変，特に小腫瘍および腫瘍様病変の臨床病理像について，病理形態学的立場から，自験例を中心に文献的考察を加えながら概説した．十二指腸は，解剖学的に腹膜後器官として固定され，組織学的には，空腸・回腸と比較し，腸絨毛が発達し粘液腺や腸内分泌細胞に富む特徴を有する．特に粘液腺が粘膜のみならず粘膜下層に豊富に分布するという他の消化管にはみられない特異性を示す．それらの特徴を背景として，非腫瘍性病変としては，異所性胃粘膜(74.5％)，アミロイドーシス(4.4％)，Brunner腺過形成(2.5％)などが，腫瘍性病変としては，腺腫(8.5％)，カルチノイド(2.9％)，腺癌(2.2％)などが比較的高頻度に認められた．病変はカルチノイドや平滑筋腫などの腫瘍性病変も含めて，粘膜下腫瘍の形態を呈するものが比較的多く，各々の臨床病理学的特徴を理解した上での臨床検査および治療が重要と考えられる．

　Anatomical and histological features of the duodenum and small pathological lesions of the duodenum, especially the small tumors and tumor-like lesions, were reviewed from standpoint of pathology with reference to the literature. The duodenum is anatomically fixed as a retroperitoneal organ and has the histological feature which intestinal villi develop and is rich in mucous glands and enteroendocrine cells as compared with those of the jejunum and the ileum. The singularity, which is not seen in other gastrointestinal tract, is shown that especially a mucous gland is abundantly distributed not only over mucosa but also over a submucosal layer. Reflecting those histological features, as non-neoplastic tumor-like lesions, heterotopic gastric mucosa (74.5％), amyloidosis (4.4％), Brunner's gland hyperplasia (2.5％), and as neoplastic lesions, adenoma (8.5％), carcinoid tumor (2.9％), adenocarcinoma (2.2％), etc. were comparatively frequent. Many of the small non-neoplastic lesions and neoplasms, such as carcinoid tumors and leiomyomas, presented the form of submucosal tumors. Therefore, it is thought that clinical examination and treatment after understanding each clinicopathological feature is important.