肝転移再発を認めたⅠp型sm癌の1例

Type-Ⅰp Submucosal Colon Carcinoma, which Showed Recurrent Metastasis in the Liver, Report of a Case

要旨　患者は40歳の女性．2001年1月ごろ便に血液が付着することに気付いた．5月に近医の注腸X線検査でS状結腸に病変を指摘され当院紹介となった．大腸内視鏡では25mm大のⅠp型のポリープで，陥凹局面を認めたためsm深部浸潤と診断し，腹腔鏡補助下S状結腸切除術を施行した．深達度はsm₂で癌先進部は中分化型腺癌，リンパ管侵襲は陽性であったが静脈侵襲やリンパ節転移は陰性であった．術後に腫瘍マーカーの上昇を示し5か月後に単発の肝転移を認めた．大腸sm癌は転移の危険因子を検討する際に，浸潤量を表面型に則した絶対値や相対分類というパラメータを用いるため，表面型と同等の転移頻度である隆起型sm癌の特徴が不透明になる可能性がある．隆起型を別途に再検討することと，既存の病理組織学的所見に加え，分子生物学的な検討を蓄積することにより，内視鏡治療の拡大と追加腸切除症例の効果的な拾い上げが可能となるものと考える．

　A 40-year-old woman had noticed bloody stool since January, 2001. Complaining of irregular defecation, she visited her nearest hospital in May. The barium enema performed at the hospital showed an elevated lesion in her sigmoid colon, and she was admitted to our hospital for a more precise diagnosis. The colonoscopic examinations showed a Ⅰp, polyp-shaped lesion 25 mm in diameter. It was diagnosed as massively invading the submucosal layer, which resulted in an irregular depression exposing the stroma on its surface.

　Laparoscopy-assisted resection in the sigmoid colon was performed. Pathologically, the lesion proved to be a moderately differentiated adenocarcinoma, massively invading the submucosal layer (sm₂) with lymphatic permeation. However, neither vessel invasion nor lymph node metastasis were detected. Five months after the operation, evidence of a single liver metastasis was detected by CT and, during the follow-up surveillance, the tumor marker increased.

　When estimating the metastasis of a submucosal invasive carcinoma, it is not valid to use parameters applying to the non-elevated type for the elevated type.

　The frequency of metastasis of the elevated-type equals that of the non-elevated type, but the characteristics of the elevation are unclear. Considering the elevated type carcinoma separately, and using molecular biological diagnosis in addition to pathological findings, we are given a wider able to choice for endoscopic therapy and can predict the metastatic potential of the submucosal invasive carcinoma.