胃癌の組織型と胃壁内進展形式

Histological Type of Gastric Carcinoma in Relation to the Mode of Intramural Spreading of Cancer Cells

要旨　胃癌の粘膜内と深部浸潤巣の組織型の変化と，粘膜内組織型と胃壁内浸潤増殖形式の検討を行った．粘膜内が分化型腺癌を示したものは，その浸潤巣で早期癌では144/208例が，進行癌では51/108例が低分化腺癌をはじめとして他の組織型に変化していた．これに対し粘膜内が低分化腺癌では，ほとんどその相違がみられなかったが，印環細胞癌はそのほとんどが低分化腺癌に変化していた．また浸潤部で低分化充実癌を示したものは，粘膜内が分化型腺癌に多くみられた．またこの中には予後の異なる髄様性リンパ球浸潤癌，あるいは内分泌細胞癌が少なからず含まれていた．更に粘膜内の分化型腺癌は胃型と腸型に分けられ，充実癌は腸型に，非充実癌は胃型に多かった．

　Study was conducted on the mode of intramural growth and spreading based on the difference in intramucosal histological type of gastric cancer. Differentiated adenocarcinoma in the mucosa, which is the primary focus of submucosal invasive carcinoma, maintained the same histological type in 149 out of 208 cases. In the remaining 64 cases, the histological type transformed to poorly differentiated and mucinous adenocarcinoma, or endocrine cell carcinoma. In advanced carcinoma with invasion below the propria muscle layer, differentiated carcinoma also showed transformation to different histological type. On the other hand, poorly differentiated adenocarcinoma in the mucosa, which is the primary focus of early and advanced carcinoma, retained almost the same histological type. However, signet ring cell carcinoma showed transformation to different histological type, poorly differentiated adenocarcinoma or mutinous adenocarcinoma, in early and advanced gastric carcinoma. Differentiated adenocarcinoma in the primary mucosal layer is likely to transform to poorly differentiated carcinoma below the submucosal layer with invasion.

　A half of differentiated adenocarcinoma in the mucosa showed solid or medullary form of growth when the gastric wall is invaded. Such lesions were histologically poorly differentiated adenocarcinoma. Poorly differentiated adenocarcinoma in the primary focus tended to develop scirrhous infiltration with fibrous stroma. Thus, the difference in histological type of the primary focus had much to do with the mode of growth or infiltration of cancer in the gastric wall below the submucosal layer.

　Differentiated adenocarcinoma was classsified into two types based on the difference in mucin histochemistry. Gastric type differentiated carcinoma showed scirrhous infiltration and intestinal type displayed solid growth in the gastric wall. Accordingly, it is important to classify differentiated adenocarcinoma into gastric and intestinal types.