粘膜下腫瘍様発育を呈した食道類基底細胞（扁平上皮）早期癌の1例

Basaloid (-Squamous) Carcinoma of the Esophagus, Report of a Case

要旨　患者は71歳，女性．心窩部の不快感を主訴に近医を受診，食道に異常を指摘され当科に紹介された．X線検査ではImに多結節性で表面に陥凹を有する隆起性病変を認めた．内視鏡では，この隆起はほぼ正常血管透見像を示す粘膜に覆われ一見大臼歯状であったが，詳細に観察すると隆起はゴツゴツとしており，隆起の一部と肛門側にヨード不染となる褪色調の粘膜が認められた（0-Ⅰ型）．隆起部の2回目の生検で中～低分化扁平上皮癌と診断されたため右開胸食道亜全摘術を行った．摘出腫瘍は25×12mmで，粘膜固有層から粘膜下層深層に位置し，食道上皮の基底細胞に類似した小型細胞の充実胞巣状増殖から成り，胞巣内外に硝子化を伴っていた．腫瘍の一部表面および辺縁の上皮内にはm1の扁平上皮癌の像もみられた．以上から深達度sm3の類基底細胞（扁平上皮）癌と診断された．リンパ節転移はなく早期癌であった．

　A 71-year-old female who was showen to have a protruding lesion on the esophagus was introduced to our hospital from Hara hospital. Endoscopic examination revealed a protruding tumor at 30 cm distal from the incisors. It was regarded as 0-Ⅰ type according to endoscopic gross classification. The tumor was almost covered with normal esophageal epithelium and the surface was not smooth but nodular. Iodine staining technique revealed an unstained area on the top and another area on the anal side of the protrusion. X-ray examination revealed, at the middle thoracic esophagus, a protruding tumor which had nodular surface and had an irregular shaped central depression. Biopsy specimen sampled from the protrusion was diagnosed as moderately to poorly differentiated squamous cell carcinoma and an operation was performed. The resected tumor, measuring 25×12 mm, was situated chiefly in the lamina propria mucosae and the submucosal layer. It was composed of atypical basaloid cells arranged in solid nests of various shapes and sizes, some of which exhibited central necrosis. Hyalinized material and foci of squamous cell carcinoma were also formed in the solid nests and in the overlyning epithelium on and near the tumor, respectively. Based on the above mentioned findings, the pathologic diagnosis was made as esophageal basaloid (-squamous) carcinoma (sm).