胃型形質の低異型度分化型胃癌の通常内視鏡診断─拾い上げ診断

Endoscopic and Histopathological Features of Low Grade Gastric Differentiated Adenocarcinoma of Gastric Phenotype for Detection during Upper Endoscopy

要旨●早期胃癌269例305病変のうち，低異型度分化型癌は99例115病変で胃型37病変，腸型78病変であった．胃型病変は発赤調，papの割合が高く，水平断端陽性になりやすい．また，腫瘍表層で微小乳頭状構造，鋸歯状変化，小型腺房状構造を呈する割合が高かった．胃型の境界不明瞭病変はL領域で，腫瘍表層の微小乳頭状構造や小型腺房状構造が認められる割合が50%未満のものが多く，H. pylori既感染が多かった．見逃し例は27.0%で，治療前の生検診断正診率は86.1%であった．胃型低異型度分化型癌は，臨床病理学的特徴を踏まえ，より微細な所見を捉え，丁寧な観察と鑑別を進めることが，見落としの少ない検査と，正確な診断・治療に必須である．

　Of the 269 cases with 305 lesions of early gastric carcinoma, 99 with 115 lesions were low-grade differentiated carcinomas, including 37 gastric and 78 intestinal lesions. The gastric-type lesions exhibited a high proportion of redness and papillary adenocarcinoma（pap）; were likely to become horizontal margin-positive ; and had a high proportion of micropapillary structures, serrated changes, and small acinar structures on the tumor surface. The gastric-type lesions were not well defined and located in the lower stomach region（L-region）. The proportion of micropapillary and small acinar structures on the tumor surface was less than 50% in many lesions. Furthermore, many patients were infected with Helicobacter pylori. There were 27% missed cases, and 86.1% cases were diagnosed based on pretreatment biopsy. For detecting a low-grade differentiated carcinoma, it is important to distinguish it from other lesions through careful observations based on clinicopathological features.