組織混在型早期胃癌の病理学的特徴

The Clinicopathologic Feature of the Early Gastric Cancer of Differentiated and Undifferentiated Mixed Type

要旨　早期胃癌1,318病変中，混在型癌は404病変（30.7％）であった．癌が進行するに従い，混在型癌の頻度は増加する傾向が認められた．混在型癌はM領域，前後壁に位置する頻度が高く，肉眼型は陥凹型が大多数を占めた．混在型癌は分化型癌および未分化型癌に比して，癌巣内潰瘍の合併率，早期胃癌におけるSM癌の割合，随伴IIb型癌合併頻度のいずれもが有意に高頻度であった（p＜0.05）．SM癌においては，混在型癌のリンパ節転移率は分化型癌および未分化型癌に比して有意に高かった（p＜0.05）．混在型癌は，非分離型（86.4％）と分離型（13.6％）に分類可能で，非分離型混在型癌はtub2とporにより構成されている頻度が高かった．非分離型混在型癌のマクロ的特徴は，褪色と胃小区不明瞭化・消失であった．分離型混在型癌は辺縁部に分化型癌，中央部に未分化型癌が配置する場合が多かった．

　We investigated 1,318 early gastric cancer lesions in this study. Histologically, of the 1,318 lesions, 404（30.7％）were mixed types. The incidence of mixed type gastric cancer tended to increase with its progress. The characteristic histopathologic findings of the mixed type gastric cancer were“located in M region of the stomach”,“located in the anterior wall or posterior wall of the stomach”,“IIc type of macroscopic type”. In the mixed type gastric cancer, both the incidence of ulceration in the tumor, the rate of submucosal invasive carcinoma, and the incidence of accompanying IIb cancer, were higher than those in the differentiated type or undifferentiated type. The rate of lymphnode metastasis in mixed type gastric cancer was higher than that in the differentiated type or undifferentiated type. We classified the mixed type gastric cancer into separated type（13.6％）and non-separated type（86.4％）. The characteristic macroscopic findings of the non-separated type of the mixed type gastric cancer were“whitish color”,“obscurity or disappearance of the gastric area”. The non-separated type of the mixed type gastric cancer consisted of tub2 and por in many cases. In the separated type of mixed type gastric cancer, differentiated adenocarcinoma tended to be located in the marginal zone of the lesion, and undifferentiated adenocarcinoma tended to be located in the central zone of the lesion.