褪色調平坦隆起の形態を呈し，上皮下を広く側方に進展し，びまん浸潤型の初期像と考えられた食道癌の1例

Esophageal Squamous Cell Carcinoma with Whitish Slightly Elevated Morphology that had Widely Invaded the Lamina Propria Mucosae, Report of a Case

要旨●70歳代，男性．上部内視鏡検査で食道に病変を指摘，生検で扁平上皮癌と診断され，当科へ紹介され受診となった．白色光観察では，切歯30cm後壁に30mm大の中央部に一段高い隆起を伴った褪色調の隆起性病変を認めた．NBI拡大内視鏡検査で病変内での血管は食道学会分類のType Aで，密度は周囲よりまばらであった．ヨード染色で病変は淡染を呈した．食道癌，Type 0-IIa＋Is，cT1b，N0，M0と診断され，食道亜全摘，3領域リンパ節郭清を施行した．切除標本の病理組織学的所見では，病変中央の隆起部の上皮直下から小さな癌胞巣が線維化を伴いながら粘膜固有層を広く側方に進展し，隆起部で固有筋層への浸潤を認めた．病変表層の大部分は非腫瘍上皮に覆われていた．リンパ節への転移は認めなかった．最終診断はMt，30mm，Type 1＋0-IIa，中分化型扁平上皮癌，pT2，pN0，sM0，fStage IIであった．

　A man in his 70s previously diagnosed with esophageal squamous cell carcinoma at a nearby hospital was later examined at our hospital. Conventional white light endoscopy revealed a whitish, flat, elevated lesion 30 mm in diameter in the posterior wall of the middle thoracic esophagus. The center of the tumor contained a sessile part. Magnifying endoscopy with narrow band imaging was used to identify the lesion as Japanese Esophageal Society classification type A. Vascular density was sparser than the surrounding mucosa. The tumor showed pale staining with iodine. Histological analysis showed that a small nest of squamous cell carcinoma cells had widely invaded from just below the epithelium into the lamina propria mucosae ; the cells were accompanied by fibrosis and had invaded the sessile part of the muscularis propria. A large part of the tumor was covered with non-neoplastic epithelium. The final diagnosis was moderately differentiated squamous cell carcinoma, T2N0M0, stage II.