Ⅱa＋Ⅱc型早期胃癌のX線診断

X-ray Diagnosis of Ⅱa+Ⅱc Type Early Gastric Cancer

　1962年内視鏡学会で早期胃癌の定義と肉眼分類が提唱されて以来，X線および内視鏡診断学の発展と技術の普及により本邦における早期胃癌の発見数は逐年的に増加し，現在では2.0～3.0cmの早期胃癌が一般開業医のレベルでも診断可能となってきた．

　Ⅱa＋Ⅱc型早期胃癌を表面隆起型Ⅱaの亜型とみれば，Ⅱaの隆起は粘膜の厚さの2倍程度と規定されているので，Ⅱa＋Ⅱc型はその程度の隆起を主体とし，一部に陥凹を有するものと定義されるであろう．この隆起の高さについての定義からいえば少しはみだしてくるが，どちらかと言うとⅡa＋Ⅱcとせざるをえない症例が存在する場合もある．

　Of 32 cases of Ⅱa＋Ⅱc type early gastric cancer, 24 were of typical doughnut shape and 8 were atypical. X-ray findings of those 24 cases have been correlated with the modes of cancer invasion and following results have been obtained regarding their x-ray characteristics.

　1. The elevated part, or Ⅱa, is sharply circumscribed against the surrounding normal mucosa with its borders mostly irregular.

　2. The surface of the elevation is nodular and of varying size. Large nodular elevations mostly show sm degree of depth invasion, while small nodular ones are m in depth infiltration, or, at most, partly sm.

　3.The excavated portion, or Ⅱc, is all irregular in shape, presenting a so-called worm-eaten picture. The presence or absence of irregular floor in the central depression has nothing to do with the degree of depth invasion.

　4. For x-ray diagnosis of Ⅱa+Ⅱc lesion radiography with compression during fluoroscopy is most important. In particular, the degree of pressure must be so proportioned that not only margins of the elevation but also its surface and the excavation itself must be visualized to the best advantage. Sometimes delineation of a worm-eaten picture in the Ⅱc part is closely bound up with the diagnosis of Ⅱa＋Ⅱc type early cancer. Double contrast study is also an excellent method in depicting the surface details of the Ⅱa+Ⅱc type lesion.