食道粘膜癌の病型分類と深達度―病理の立場から

Esophageal Mucosal Cancer: Classification and the Depth of Invasion from the Pathological Point of View

要旨　食道粘膜癌108例について，新たに提案された深達度亜分類を用いて病理組織学的検討を加えた．粘膜癌の深達度亜分類の定義は，以下の通りである．m₁：上皮内癌および，上皮内癌かわずかに粘膜固有層に浸潤した癌か区別のつきにくいもの．m₂：m₁，m₃以外．m₃：癌浸潤巣が粘膜筋板に極めて近接したり，あるいは浸潤するもの．粘膜癌の肉眼型はすべて0-Ⅱ型で表され，微小癌を除くと，単純型の割合が74％，0-Ⅱc型が71％であり，0-Ⅱc型を主体とする病変はおよそ91％である．0-Ⅱc型は深達度が深くなると，0-Ⅱa型の要素が加わるものがみられる．0-Ⅱa型，0-Ⅱb型はほとんどが深達度m₂までの比較的浅い癌である．今回の検討では，粘膜癌にはリンパ節転移，静脈侵襲はみられなかったが，リンパ管侵襲はm₂で3％，m₃で27％にみられた．組織学的異型度は，深達度が深くなるにつれて異型の強くなる傾向がみられた．深達度亜分類を用いることにより，粘膜癌の多くの臨床病理学的事項は集約されると言える．

　We evaluated 108 cases of mucosal cancer of the esophagus using the newly developed pathohistological sub-classification. The sub-classification is defined as follows: m₁; intra-epithelial cancer and/or mucosal cancer with invasion to the lamina propria mucosae which is difficult to distinguish from intra-epithelial cancer. m₂; mucosal cancer with invasion between m₁ and m₂. m₃; mucosal cancer almost and/or already invading the lamina muscularis mucosae.　The macroscopic appearance of all mucosal cancer was classified into type 0-Ⅱ. Except for minute cancer, 74% of esophageal mucosal cancer was simple type, and 71% was type 0-Ⅱc, and 91% of mucosal cancer included principally type 0-Ⅱc lesions. Some of the type 0-Ⅱc lesion accompanied a component of type 0-Ⅱa lesion as invasion reached the deeper layers. Most of the type 0-Ⅱa and 0-Ⅱb lesions were relatively less invasive and were limited to m₂ stage. In our study, although no mucosal cancer was accompanied by lymph node metastasis and venous invasion, 3% of m₂ and 27% of m₃ stage mucosal cancers had lymphatic invasion. The severity of histological atypia might progress with the depth of invasion. In conclusion, sub-classification of the invasivity can describe most of the clinicopathological features of mucosal cancer of the esophagus.