上皮下病変様の形態を呈した低分化食道扁平上皮癌の1例

Poorly Differentiated Esophageal Squamous Cell Carcinoma with Subepithelial Tumor-like Morphology：a Case Study

要旨●患者は60歳代，男性．定期サーベイランス目的の上部内視鏡検査で，食道病変を指摘した．病変のほとんどを非腫瘍上皮で被覆され，上皮下病変様の形態であった．内視鏡的に扁平上皮癌の上皮内進展を疑う所見は指摘できなかったが，病変の一部に，不規則に分枝/走行する細かい不整血管を認め，上皮下に腫瘍の存在が疑われ，生検で低分化扁平上皮癌の診断となった．上皮下病変様の食道癌は，内視鏡観察可能な露出部が少ないために病変の指摘が難しく，粘膜下層以深に浸潤している場合が少なくない．また，ヨード染色後は病変範囲がさらに不明瞭になり，範囲診断も難しい症例であった．

　This is a case of a man in his 60s. An esophageal lesion was identified during a routine upper endoscopy for surveillance. The lesion was mostly covered with nontumorous epithelium and exhibited a subepithelial tumor-like morphology. Although no clear signs suggested the intramucosal extension of squamous cell carcinoma upon endoscopy, irregularly branching and running fine vessels were observed within a portion of the lesion. This increased our suspicion of the presence of a tumor beneath the epithelium. Subsequent biopsy confirmed the diagnosis of poorly differentiated squamous cell carcinoma. Detection of esophageal cancer with a subepithelial tumor-like appearance can be challenging because of limited surface exposure, often infiltrating deep into the submucosal layers. Furthermore, the extent of the lesion became even more indistinct after iodine staining making it difficult to determine its precise boundaries in this case.