陥凹内にドーム状隆起を形成したsm微少浸潤大腸癌の1例

Depressed Type of Colon Cancer with Dome-shaped Central Growth, Report of a Case

要旨　患者は64歳の男性で，腹部膨満感を主訴に大腸内視鏡検査を行ったところ，S状結腸に陥凹内に隆起を形成した病変が認められた．生検でgroup5の診断を得，当院入院となった。術前の注腸X線検査および内視鏡検査で，星芒状の境界を示す陥凹の中心に，ドーム状の隆起を認めた．しかし，形態は空気量によって著明に変化した．S状結腸部分切除が行われ，病理組織学的には径15×11mm，Ⅱc＋Ⅱa型，深達度sm1の高分化腺癌であった．陥凹内隆起形成は癌のsm多量浸潤によって形成されることが多いと考えられていたが，本例の陥凹内隆起の主体は癌の粘膜内増殖によって成り立っていた．

　A case of depressed type early colon cancer in a 64-year-old male was reported. Double contrast barium enema disclosed a shallow depressed lesion with central elevation, 1.8×1.5 cm in diameter in the sigmoid colon. Colonoscopy revealed a reddish depressed lesion with dome-shaped central growth in the sigmoid colon. Biopsy specimens of the lesion revealed a well differentiated adenocarcinoma. Therefore, sigmoid colectomy was performed and the histologic examinations showed a well differentiated adenocarcinoma invading the superficial submucosal layer. No lymph node metastasis was found. It has been considered that depressed type colon cancers with central elevation are characterized by frequent deep submucosal invasion. In the present case, however, the dome-shaped central elevation consisted of intramucosal growth and a slight submucosal invasion of the carcinomatous glands.