拡大内視鏡による胃癌の組織型の診断─未分化型癌

Magnifying Narrow Band Imaging of Undifferentiated-type Carcinoma in the Stomach

要旨●内視鏡的に切除した胃未分化型癌34症例35病変を検討した．NBI拡大観察では，不規則に分枝・蛇行しながら次第に細まっていく血管像（wavy micro-vessels）が特徴的であり，多くの病変では窩間部開大所見やcorkscrew patternも併存して認められた．H. pylori未感染例のsig単独3病変は，血管所見を伴わず窩間部開大のみを認め，開大した円形〜楕円形と溝状の腺開口構造が観察された．微細構造の消失と血管密度の低下を伴うcorkscrew patternを示した病変の中に，既存の集合細静脈から分枝する所見がみられ，wavy micro-vesselsは癌浸潤を反映した既存の微小血管所見と考えられた．未分化型癌の拡大内視鏡診断では，癌自身の所見ではなく，癌と非癌上皮との複合所見を観察していることを理解する必要がある．

　We evaluated 35 early, undifferentiated gastric cancers that were identified in 34 patients who underwent endoscopic submucosal dissection. Narrow-band imaging with magnifying endoscopy of the undifferentiated cancers revealed combinations of the expanded intervening part, wavy microvessel, and corkscrew patterns. The wavy microvessel and corkscrew patterns were identified in the undifferentiated cancers involving to the surface and mucosal layers, respectively. Microsurface patterns of the expanded intervening part were useful for recognizing undifferentiated cancers that had spread into the mucosal neck zone. Signet ring cell carcinomas without Helicobacter pylori infections were correlated with the findings of the expanded intervening part. In some lesions of the corkscrew patterns, wavy microvessels were derived from preexisting collecting venules. To make an accurate diagnosis of the undifferentiated cancers, understanding the combination appearances between cancer cells and non-cancer microvessels is recommended.