転移を来した胃粘膜内癌の内視鏡所見の検討

Endoscopic Findings of Intramucosal Gastric Cancer with Metastasis

要旨　外科手術を行った胃粘膜内癌1,727例中リンパ節転移陽性は26例（1.5％）であった．転移陽性例は女性に多く，平均年齢が51.4歳と若年であった．平均径は43mmと大きく，未分化型，癌巣内潰瘍合併が各々20例，23例を占め，脈管侵襲陽性例の転移率が高かった．癌巣内潰瘍を有する未分化型癌では10mmを超えると転移陽性例が現れ，全体では5.0％に達した．従来の報告と異なり，30mm以下の分化型癌，癌巣内潰瘍のない分化型癌でも，リンパ節転移例が存在した．粘膜内癌の転移リンパ節および転移巣は小さいため，手術所見で転移陽性と正診できたのは15.4％に過ぎなかった．転移陽性26例の累積10年粗生存率は96％と良好であった．20mm以上の癌巣径，粘膜下要素，未分化型癌と推定される褪色調のうち2つ以上の内視鏡所見を有するものが22例中20例にあり，リンパ節転移陽性粘膜内癌の内視鏡像として重要であると考えられた．

　Of 1,727 patients operated on for gastric intramucosal cancer in our hospital, 26 patients (1.5％) had lymph node metastasis. Female patients had more lymph node metastasis than male and the average age of node-positive patients was younger (51.4 years) than node-negative patients. The average diameter of cancers with lymph node metastasis was larger (4.3cm) and the histological type was undifferentiated in 20 patients. Ulceration was found in the cancerous lesions of 23 patients. There was significant relation between lymph node metastasis and invaded vessel. Lymph node metastasis was found frequently in patients with undifferentiated-type cancer with ulceration more than 10mm in diameter. Contrary to conventional reports, we found lymph node metastasis in differentiated-type cancer less than 30mm in diameter, or differentiated-type cancer without ulceration in the cancerous lesion. Because both metastatic lymph nodes and metastatic foci in lymph nodes were small, only 15.4％ of patients were operatively diagnosed as having positive lymph node metastasis. The cumulative ten-year survival rate by Kaplan-Meier method was estimated as 96.0％ for 26 patients having intramucosal gastric cancer with lymph node metastasis. We judged that diameter more than 20mm, submucosal components and pale color lesion peculiar to undifferentiated-type cancers were the important endoscopic findings for intramucosal gastric cancer with lymph node metastasis.