早期食道癌のX線深達度診断―正面像の解析から

Radiological Estimation of Extent and Depth of Invasion of Early Esophageal Cancers

要旨　早期食道癌のX線正面像による深達度と拡がりの診断を検討した．その結果，0-Ⅱc型病変の深達度ごとのX線形態が明らかになった．m₁～m_2a癌の88％は平坦または不鮮明な模様のごく軽度の陥凹であり，m_2b癌では78％が明らかな顆粒を伴う軽度陥凹として描出された．m₃～sm₁癌は軽度陥凹＋隆起（53％），中等度陥凹（47％）の2つの病型を示し，粘膜筋板浸潤部にひだの肥厚所見がみられた．病変の拡がりは，粘膜ひだの不整と陰影斑の所見から82％の症例で診断可能であった．O-Ⅱa型病変でも病変の形態が重要で，顆粒集簇型と結節隆起型を呈する84％の症例では隆起の高さと大きさによって深達度診断が可能であったが，単発隆起型（16％）の診断は不十分であった．

　In order to clarify radiological features of extent and depth of invasion in cases of early esophageal cancers, esophagograms of fifty eight type 0-Ⅱc (slightly depressed) lesions were analyzed. Radiological findings which represented each depth of invasion (esophageal cancer confined to the epithelium: m₁, the lamina propria mucosae: m₂, reaching to the muscularis mucosae: m3 and those invading slightly into the submucosa: sm1) were studied.

　In cases with m1 (20 lesions) and m_2a (those with cancer infiltration slightly into the lamina propria mucosae: 14 lesions) cancers, 88% of all lesions showed minimal depression with smooth surface or slight undulation. In cases with mucosal cancer infiltrating into the deeper half of the lamina propria mucosae (m_2b: nine lesions), 78% of all lesions showed mild depression with well defined granules. In cases with m₃ (eight lesions) and sm₁ (seven lesions) cancers, either large granules in a mild depression or slight elevation in a moderate depression was noted. Abnormalities of longitudinal mucosal folds suggested extent of cancer lesions: irregularity of width of folds was suggestive of extent of m₁ cancer. On the other hand, tall and wide mucosal folds indicated cancer invasion into the muscularis mucosae or ever deeper. Accuracy rate of differentiation of m1 and m2 cancers from m3 and sm₁ was 91%. Histological features of lesions with failed estimation of depth of invasion were m3 cancers narrowly reaching to the muscularis mucosae and sm1 cancers with infiltration replacing the epithelium of the ducts of esophageal glands.