2か所に同時多発を認めた食道扁平上皮癌の1例

Double Primary Squamous Cell Carcinomas of the Esophagus, Report of a Case

要旨　患者は48歳，男性．タバコ20～30本/日・アルコール2～3合/日25年間．祖母に喉頭癌．1996年10月検診の上部消化管X線検査の結果，食道の粘膜模様異常を指摘された．内視鏡検査を施行し，Utに発赤調で中央に結節状隆起を伴う長径約4～5cm，ほぼ全周性の0-Ⅱc＋Ⅱa型病変と，Mtに血管透見不良を示す長径約2cmの0-Ⅱb型病変を認めた．X線・内視鏡検査で主病変の深達度SM₂，副病変m₁と診断された．切除標本では，主病変は43×38mm，組織学的に角化のない低分化型扁平上皮癌が粘膜下層に広範に浸潤し，リンパ管侵襲が高頻度に認められた（sm₃，ly₃，v₀）．副病変は16×12mm，粘膜内病変であった（m₁，ly₀，v₀）．病変周囲粘膜にはdysplasic squamous epitheliumが広範囲に存在していた．本症例は多中心性に発生した同時多発の扁平上皮癌と考えられた．

　A 48-year-old male visited the Foundation for Detection of Early Gastric Carcinoma for a yearly examination of the upper gastrointestinal tract. Radiographic and endoscopic examination revealed two lesions of esophageal carcinoma. One of them (main lesion) was a superficial and slightly depressed type with nodular surface at the upper thoracic esophagus (Ut), the other (second lesion) was a superficial and flat type at the middle thoracic esophagus (Mt) separated by a distance of 4～5 cm distal from the main lesion. Simple resection was performed with a diagnosis of double esophageal carcinoma with submucosal invasion.

　Macroscopic findings showed that the main lesion was an 0-Ⅱc+Ⅱa type, measuring 43×38 mm at the Ut portion, and the second lesion was an 0-Ⅱb type, measuring 16×12 mm at the Mt portion. Histologically, poorly differentiated squamous cell carcinoma had deeply invaded the submucosal layer (sm₃) with lymphatic invasion in the main lesion, while the carcinoma was within the mucosal layer (m₁) without vessel invasion in the second lesion. Dysplastic squamous epithelium with moderate to severe atypia was present surrounding both lesions, suggesting that both carcinomas in this case might have been primarily of multicentric origin.