Ⅱa＋Ⅱc型早期大腸癌の1例

Ⅱa＋Ⅱc Type Early Cancer of the Large Intestine, Report of a Case

要旨　患者は53歳，男性．主訴は軟便，貧血．黄疸なし，便潜血（+++），CEA（－），生化学的に肝硬変症あり，大腸X線・内視鏡検査で肝彎曲部に中央がわずかに陥凹し，辺縁部に小結節が連なる病変を認め，その表面には細かく大小不同のない模様がみられたことより，深達度の浅いⅡa＋Ⅱc型早期大腸癌と診断した．右半結腸切除術を実施，肝彎曲部に周囲粘膜と同様の色調を呈する2.4×2.1cmのⅡa＋Ⅱc型病変を認めた．病理学的に高分化型腺癌であったが，分化度に多様性があり，腺腫と鑑別が難しい部位も存在した．深達度はごく一部でsmに達し，ly₀，v₀，n（－）であった．本例は平坦な大腸癌の診断上，また大腸癌の発生を考えるうえで貴重な症例と思われる．

　A 53 year-old man was reffered to our hospital for exact diagnosis of an abnormal radiological finding in the colon. He had had loose stool in the past several years. Blood chemistry was abnormal due to hepatic cirrhosis and stool was positive for occult blood. Radiological and colonoscopic studies showed a sessile lesion with shallow central depression at the hepatic flexure of the colon (Figs. 1 and 2). Biopsy specimens were interpreted as carcinoma with tubular adenoma. Operation (right hemicolectomy) was performed on November 27, 1984. Macroscopic diagnosis was Ⅱa ＋ Ⅱc type early cancer of the large intestine, measuring 24×21 mm in diameter (Fig. 3). Histological diagnosis was well differentiated adenocarcinoma which showed various degrees of atypia (Fig. 4 a～d). Cancerous invasion was limited to the mucosal layer with a minimal infiltration into the submucosal layer (Fig. 4 a, e).

　This case has valuable implications in diagnosing early cancer of the large intestine by radiology and endoscopy.