表在型食道扁平上皮癌に合併した類基底細胞癌の1例

Superficial Squamous Cell Carcinoma Concomitant with Basaloid Carcinoma of the Esophagus, Report of a Case

要旨　患者は76歳，男性．嘔吐を契機に受けた上部消化管内視鏡検査で，食道の異常を指摘され当科紹介となった．食道造影では，Mt領域に0-Ⅰpl型，Lt領域に0-Ⅰpl型食道癌の所見を認めた．内視鏡検査では，上切歯列より32cmの食道に頂部にびらんを有する0-Ⅰsep型，37cmに表面に結節，顆粒を有する0-Ⅰpl型食道癌を認めた．いずれも推定深達度Tlb（SM）であり，生検で扁平上皮癌と診断され，食道切除術が施行された．切除標本では，口側病変は，食道類基底扁平上皮癌，深達度Tlb（SM2），肛門側病変は，中分化型扁平上皮癌，深達度Tlb（SM3）と診断した．扁平上皮癌と類基底細胞癌の合併はまれであり，また，比較的近傍に2つの病変が存在することより，field carcinogenesisの可能性を示唆する所見であり，食道癌の発生，悪性度を考えるうえで貴重な症例であると考えられた．

　A case of superficial esophageal carcinoma concomitant with basaloid carcinoma of the esophagus was encountered. The patient a 76-year-old male, was admitted to our hospital with vomiting as his main complaint. Esophagography demonstrated an elevated lesion at the middle of the esophagus and a flat elevated lesion with nodular and granular surface at the lower part of the esophagus. Esophagoscopy showed a discolored elevated lesion with erosion 32 cm below the level of the incisors, and a flat elevated lesion with nodular and granular surface 37 cm below the incisors. The biopsy specimens revealed squamous cell carcinoma. A blunt dissection of the thoraco-abdominal esophagus with retrosternal gastric tube replacement was performed. In the histological examination of the resected specimens, the oral-side tumor revealed basaloid squamous cell carcinoma invading the submucosal layer of the esophagus and covered with normal squamous epithelium, and the oral-side tumor revealed squamous cell carcinoma of the esophagus invading the submucosal layer. This case is rare and important from the point of veiw of field carcinogenesis. and is interesting become of the carcinogenesis and biological behavior of the esophageal carcinoma.