食道表在癌肉眼分類の新しい提案―病理の立場から

Proposal of a New Macroscopic Classification of Superficial Esophageal Cancer from a Pathological Veiwpoint

要旨　食道表在癌48症例62病変を用いて，食道表在癌の肉眼分類を提案すると共に，その特徴を検討した．食道表在癌の肉眼型は早期胃癌分類に準じて病変の高低差でⅠ型（隆起型），Ⅱa型（表層隆起型），Ⅱb型（平坦型），Ⅱc型（表層陥凹型），Ⅲ型（潰瘍型）の5型に分類できた．本分類は癌深達度とよく相関し，Ⅰ型は100％sm癌であった．Ⅱa型では72.7％がsm癌で隆起病変は癌のsm浸潤を示唆する所見であった．Ⅱb型は7.7％がsm癌であったのに対し，Ⅱc型では40％がsm癌であった．陥凹病変も癌のsm浸潤を疑わせる所見であった．今回の検討ではⅢ型は認められなかった．本分類に病変部の肉眼表面構造を加味することで一層正確に癌の深達度を推定することが可能であった．

　We proposed a new macroscopic classification of superficial esophageal cancer: Type Ⅰ (protruded type), Type IIa (superficially elevated type), Type Ⅱb (flat type), Type Ⅱc (superficially depressed type), and Type Ⅲ (excavated type).

　Sixty-two lesions of superficial esophageal cancer were classified according to this new classification and analyzed to define the features of each type. This classification reflected very well the depth of cancer invasion: all cases of Type Ⅰ and 72.7% of Type Ⅱa were invasive cancer down to the submucosa (sm cancer).

　Protrusion or elevation was among the important findings which suggested sm cancer. Invasion to the submucosa was also noted in 40% of Type Ⅱc, while only in 7.7% of Type Ⅱb. Thus, depression did also suggest sm invasion. Furthermore, close observation of the surface structure, in addition to this new classification, of cancerous lesion helped us estimate more precisely the depth of cancer invasion macroscopically.