食道扁平上皮癌と乳頭腫の鑑別診断

Differential Diagnosis of the Superficial Esophageal Cancer and the Esophageal Squamous Papilloma

要旨●食道乳頭腫に形態が類似した食道表在癌の特徴と鑑別点を検討した．2012年4月〜2019年3月に拡大内視鏡を用いた検査で発見した食道乳頭腫は51例55病変あり，その形態はイソギンチャク型が39病変（71%），桑実型が16病変（29%）で，長径5mm以下が大半を占めた．同期間中に食道乳頭腫と形態的に鑑別を要した食道表在癌は3病変であった．いずれも桑実型に類似していた．鑑別点は微細顆粒の形態や大きさが不揃いで，血管形態も不均一であることが挙げられたが，乳頭腫と非常に類似して鑑別が難しい部分も存在した．乳頭腫の血管は周囲を過形成性の扁平上皮で覆われているためヨード染色すると白点模様を有する正染を示すが，食道癌は不染になることが大きな相違点と考えられた．溝状の陥凹や不均一な表面構造は深部浸潤を示唆する所見と考えられた．

　We examined a characteristic and differential point of the superficial esophageal cancer morphologically similar to an esophageal squamous papilloma. Fifty-five lesions of esophageal squamous papilloma were detected in 51 cases examined using magnifying endoscopy from April 2012 to March 2019. Morphologically, the sea anemone-like form was observed in 39 lesions（71%）of the esophageal squamous papilloma, while the mulberry-like form was observed in the remaining 16 lesions（29%）. Also, longer axis of less than 5 mm was observed in most of these lesions. Three lesions of the superficial esophageal cancer were morphologically well-differentiated with an esophageal squamous papilloma during the same period. All were similar to the mulberry-like form. The differentiation points（the form and the size of the minute granule）were uneven, and the microvessels were heterogeneous in form, but the part very similar to the esophageal squamous papilloma and poorly differentiated also existed. The esophageal squamous papilloma was stained with iodine because its micro-vessels were covered with hyperplastic squamous epithelium. In contrast, the fact that the superficial esophageal cancer was unstained with iodine was believed to be a huge difference. Our findings suggested the presence of a deep invasion due to the formation of the sulcus and the heterogeneous surface structure.