内視鏡的粘膜切除術を施行した胃sm癌―病理診断の問題点

Gastric sm Cancer Resected by EMR, Problems of Pathological Diagnosis

要旨　内視鏡的粘膜切除術(EMR)をされた胃sm癌17例について垂直方向への浸潤を軸に脈管侵襲，切除端，リンパ節転移，予後などについて検討した．リンパ管侵襲はsm浸潤部が垂直方向で500μm未満の7例では2例(28.6％)に，500μm以上の10例では9例(90％)に認められた．深部切除端(粘膜下層面)で癌の露出を認めた5例は垂直浸潤が1,000μmを超えていた．局所での癌の遺残，再発は2例で，リンパ節への転移は1例に認められた．EMR標本では粘膜下層が疎となり厚く判定される傾向があり，微少浸潤の境界を500μmまで下げられると考えられた．また断端遺残の判定にはいわゆるburnning effectを考慮する必要があると考えられた．

　The vascular involvement, tumor invasion of the cut end, lymph node metastasis and prognosis of seventeen cases of gastric sm cancer resected by EMR were analyzed by the depth of invasion. As for the lymph vessel invasion, only two out of seven cases (28.6%) with sm invasion less than 500 μm in depth had lymphatic vessel invasion compared to nine out of 10 cases (90%) with sm invasion deeper than 500 μm. All of the five cases with tumor invasion of the cut end (submucosal surface) had invasion deeper than 1,000 μm. Local recurrence and/or remnant were found in two cases, and lymph node metastasis was detected in one case. The submucosal layer of the EMR specimens was rough and was likely to be judged thicker, therefore criteria of the microinvasion might be changed to 500 μm in depth. So-called burning effect should be taken into consideration for the judgement of remnant of tumor at the cut end.