10mm以下の大腸sm massive癌の病理学的特徴

Pathological Characteristics of Colorectal Sm Massive Carcinoma Less than 10 mm in Diametor

要旨　外科切除大腸sm癌341病変を対象とした．絶対値sm浸潤度分類でsm垂直浸潤長1,000μm以上を，相対値sm浸潤度分類でsm_{2, 3}を，それぞれsm massive癌とした．10mm以下sm massive癌はsm massive癌全体の12.2％(35/288)(絶対値分類)，9.2％(22/240)(相対値分類)を占めた．10mm以下絶対値分類sm massive癌のリンパ節転移陽性率は20％(3/15)で，10mmより大の同癌と有意差はなく，10mm以下sm massive癌も10mmより大の同癌と同等の臨床的取り扱いをすべきと考えられた．10mm以下相対値分類sm massive癌はde novo発生の表面型(特に表面平坦・陥凹型)癌を起源粘膜内癌とすると考えられた．10mmより大sm massive癌の81.3～89.1％は10mm以下sm massive癌を前駆段階としておらず，両者は異なる発育進展経路をたどる癌と考えられた．

　Three hundred and forty-one colorectal submucosal carcinomas were studied. sm massive carcinoma (sm-m) was defined by either absolute value (depth of sub-mucosal invasion being 1,000μm or more) or relative value (sm₂, sm₃) of submucosal invasion. sm-m 10 mm or less (sm-m≦10) occupied 12.2％ (35/288) (by absolute value) and 9.2％ (22/240) (by relative value) of all sm-m, respectively. 20％ (3/15) of sm-m≦10 (defined by absolute value) showed lymph nodal metastasis and the frequency revealed no significant difference to sm-m of more than 10 mm (sm-m＞10). Therefore, sm-m≦10, when defined by absolute value, should be treated as equal to sm-m ＞ 10. sm-m≦10 (defined by relative value) were regarded to have originated in superficial (especially superficial flat or depressed) type of de novo mucosal carcinomas. 81.3 to 89.1％ of sm-m ＞ 10 showed no histological continuity with sm-m≦10, and the sm-m≦10 and sm-m ＞ 10 defined by relative value were thought to be on a different line of development of the colorectal carcinoma.