リンパ節転移を有する胃分化型SM1癌の特徴

Features of Lymphnode Metastasis Cases of Early Gastric Cancer―"SM 1" as Their Degree and "Well-Differentiated Cancer" as Their Histology

要旨　胃分化型SM癌を，癌研Broders分類を用い，分化型純型（高分化，中分化：癌研Broders分類2a，2b），分化型混合型（高，中分化優位，低分化型成分あり：癌研Broders分類2a，2b＞3，4）に亜分類し，リンパ節転移について検討した．胃分化型SM癌は556例あり，分化型SM癌でのリンパ節転移率はそれぞれSM1：3.8％，SM2：12％であった．SM1に関しては分化純型0％，分化型混合型4/34（12％）と，転移例はすべて分化型混合型であった．4例中3例はUl（＋）例であった．脈管侵襲は全例にみられた．SM浸潤部の組織型はBroders分類の2a（高分化型），2b（中分化型）であり，粘膜内に低分化成分（3，4）がみられる症例が4/4（100％）例あった．粘液形質では2/4（50％）が腸型，2/4（50％）が胃型であった．これに対し，SM2以深の分化型純型，分化型混合型のリンパ節転移例での粘液形質はそれぞれ，分化型純型で胃型28％，腸型32％，分化型混合型で胃型52％，腸型7％と分化型混合型においては胃型形質の発現を半数に認めた．胃分化型SM1癌の転移例の特徴としては全例脈管侵襲陽性であること，必ずしも深部浸潤部の組織型が低分化ではないことと，瘢痕を伴う病変であった．

　We studied lymphnode metastatic early gastric cancer cases which were well differentiated adenocarcinomas whose depth was SM1. There were 556 submucosal invasive cases, among which 3.8％ of SM1 cases were lymphnode metastatic and 12％ of SM2 cases were well-differentiated adenocarcinoma. We divided the well-differentiated adenocarcinoma into two types, size. (1) purely well-differentiated type and (2) partially well-differentiated type with the major component being well-differentiated and the minor component being poorly differentiated. There were 4 metastatic cases among the SM1 and well-differentiated group (1). All the lymphnode metastatic cases were from the mixed type (2). Three out of four (75％) of the cases had ulcer scar in their lesion and also had lymphatic permeation. All of these three cases were well differentiated adenocarcinoma at their submucosal invasive point. Half of the four metastatic cases were gastric type in mucous differentiation.