特殊型胃癌の病理学的特徴

Macroscopic and Microscopic Pathology of Special Types of Gastric Carcinoma

要旨　「胃癌取扱い規約第14版」によると，発生頻度の低い胃癌は特殊型に分類される．この特殊型胃癌のなかには生物学的振る舞いが侵攻性で臨床的に極めて高悪性度の癌が含まれており，胃癌診療の現場では，その臨床病理学的特徴を理解しておく必要がある．特殊型胃癌は腫瘍の発育様式と増殖能により，様々な肉眼像を呈し，また病巣部粘膜内に腺癌が併存するものは一般型胃癌の特徴を部分的に併有しうる．以上の肉眼的特徴の指摘とともに特殊型胃癌の組織像を供覧した．

　According to the general rules of Japanese classification of gastric cancer（14th edition）, gastric carcinomas are classified into a common or a special type. Generally, the incidence of special types is low. Some of the special types（e.g. endocrine cell carcinoma or hepatoid adenocarcinoma）are particularly aggressive, malignant neoplasms. Therefore, it is necessary for clinicians and pathologists to know about the clinicopathologic features of the special types. The gross appearance of the special types are characterized by growth pattern and/or proliferative activity. The special types sometimes coexist with distinct adenocarcinoma components, and therefore resemble, in part, the macroscopic appearance of the common types. We pointed out the above-mentioned pathologic features and demonstrated the microscopic figures.