2）組織型

Histological Types of Early Gastric Cancer

要旨　早期胃癌の組織型について検討した．早期胃癌には高分化型および中分化型管状腺癌，印環細胞癌が多くを占める．M癌では高分化型管状腺癌が半数を占め，次いで印環細胞癌が多い．SM癌では中分化型管状腺癌や非充実型低分化腺癌の割合が相対的に増加を示した．組織型の多様性についてみると，微小癌の大部分が単一型であるが，小胃癌では混合型が30.8％にみられた．また，20mmまでのSM癌では70.8％が混在型であった．組織型診断の問題点を頻度の高い管状腺癌と印環細胞癌について述べたが，低異型度の高分化型管状腺癌が日常診断で特に問題になると思われた．さらに，分化型・未分化型の二分類について概説した．

　Most histological types of early gastric cancer are tubular adenocarcinoma and signet-ring cell carcinoma. In M cancers, about half are well differentiated tubular adenocarcinomas, and then come signet-ring cell carcinomas. In SM cancers, ratios of moderately differentiated tubular adenocarcinomas and poorly differentiated adenocarcinomas are increasing. As for histological diversity early cancer, most microcancers are of the simple histological type, and 30.8% of small cancers are mixed histological types. 70.8% of SM cancers less than 2cm in size are mixed histological types.

　It is difficult to diagnose well differentiated tubular adenocarcinomas of low grade as cancerous glands. Most of them show gastric mucin phenotype. So not only the pathologist but also the clinician should be capable of discerning the type of cancers confronting him.