色素内視鏡により境界が明瞭となった広範囲Ⅱb＋Ⅱc型早期胃癌の1例

Superficial-Spreading Early Gastric Cancer Type Ⅱb＋Ⅱc with Its Intramucosal Extension Well-Visualized Chromoscopically, Report of a Case

要旨　広範囲Ⅱb＋Ⅱc型早期胃癌症例（62歳，男性）．tub₂，sm，53×74mm．癌巣の内部に非連続性に3個の浅い陥凹部（Ⅱc）を有し，その他の広い範囲において平坦な癌巣の浸潤範囲を，筆者らが考案したブリリアントブルー法（BB法）色素内視鏡検査によって術前に正しく診断しえた．通常内視鏡およびX線検査によって病巣の質的診断および範囲決定は困難であったが，BB法によって癌巣を取り囲む高度腸上皮化生粘膜は青色調を呈し，一方癌巣は対照的に不整形の赤機色領域を呈した．

　A man, 62 years of age, with early gastric cancer type Ⅱb＋Ⅱc of a size 53 by 74 mm, with a wide range of intramucosal infiltration and with a focal invasion into the submucosal layer is reported. The purpose is to report that the preoperative determination of the cancerous territory, so ill-defined as to be indistinguishable on the resected specimen, was successfully attained by a chromoscopic observation with the use of Brilliant Blue (BB), and that observation under a dissecting microscope of the resected specimen fixed with formalin and stained with Methylene blue (MB) was useful in grossly determining the cancerous territory prior to a histological study of sectioned materials.

　Despite the recent development of techniques of endoscopic diagnosis, it is still difficult to circumscribe preoperatively the range of cancerous infiltration in such a flat lesion as presented here.

　With application of chromoscopic pretreatment with BB (Table 1), an endoscopic visualization (Fig.1) of the entire range of cancerous infiltration was obtained, and the preoperative determination of the oral-side limit of cancer led to a successful surgical resection of the entire lesion with subtotal gastreotomy.

　The resected stomach (Fig. 3) was fixed with a 10% formalin solution (Fig. 4), stained in 2000ml of a 0.005% MB solution, and then inspected under a dissecting microscope (Fig. 6). A territory with a destruction of such patterns of surface fine structure as a frweolar-sulciolar pattern or a mesh-like pattern described by T. Yoshii was circumscribed, and a histological examination including the territory was performed. The reconstruction of the cancerous infiltration (moderately differentiated adenocarcinoma) was shown schematically in Fig. 5. The orange area represents the range of Ⅱb (mucosal), the red area that of Ⅱc (mucosal), and the dotted small area represents that of submucosal infiltration.