表層拡大型の胃型高分化型腺癌の1例

A Revealing Superficial Spreading Type Well Differentiated Adenocarcinoma of Gastric Phenotype, Report of a Case

要旨　患者は66歳，男性．胃角から前庭部の大彎を中心とし前後壁に広がる表層拡大型病変．X線検査では，後壁側にみられる微細なバリウム斑を伴うやや粗大な顆粒状変化と，前壁側の粗大な偽足様に広がる透亮像を示した．内視鏡では，腸型にみられる褪色調で菊花状の辺縁を有する平板状の隆起とは異なり，全体に柔らかい印象を持ち，後壁側では淡い発赤調で大小不同のやや粗大な顆粒状隆起の集簇で，境界は不明瞭．前壁側では偽足様の発育を示す暗赤色調の境界明瞭な隆起として認められた．生検で高分化型管状腺癌を認め外科的手術を施行した．病理組織学的には95×50mmの表層拡大型．P Type 0 IIa＋I，高異型度の高分化型管状腺癌が主体で乳頭腺癌が混在し，低異型度部分と中分化腺癌の像も認めた．粘液形質はMUC-5AC強陽性，M-GGMC-1，MUC-2，CD10はそれぞれ陰性で胃腺窩上皮型を示し，深達度は粘膜下層に浸潤するsm1癌であった．本症例はいわゆる腸型の分化型癌とは異なり，いくつかの特徴的所見を持つ表層拡大型の胃型分化型癌と考えられた．

　A male at the age of 66 presented a superficial spreading lesion along the greater curvature from the angular part to the pyloric antrum extending to the anterior and posterior wall sites. Radiograms revealed coarse granules varying in size and accompanying fine barium flecks on the posterior wall site. In addition to this, a flat-topped elevation featuring pseudopodia growth on the anterior wall site was also observed. Endoscopically, apart from the characteristics of intestinal type, which not infrequently manifest a monotonous and chrysanthemum-like plateau, as a whole, the lesion looked reddish and had a roundish contour. Vaguely reddened congregated granules varying in size were discerned on the posterior wall site, but occupied no distinct territory. However on the anterior wall site, a well delineated elevation of psudopodia showing a dark-redish hue, indicative of l ateral spreading expansive growth, was discerned. Following a surgical operation, the lesion was diagnosed as a superficial-spreading type (95×50mm), 0-IIa＋I, sm1 cancer, predominantly composed concominantly of highly atypical well differentiated adenocarcinoma, papillarly adenocarcinoma, low grade atypia, and moderately differentiated cancer. With the mucus phenotype, MUC-5AC being strongly positive, and the MUC-2 and CD10 being both negative, the lesion was concluded to be a gastric foveolar type of cancer. To sum up, the present case could be characterized by the aforementioned findings, and its difference especially from intestinal type cancer cannot be over stressed.