pit patternからみた大腸表面型腫瘍の深達度の推定

Estmation of the Depth of Invasion of the Superficial Type of Colorectal Tumor by Pit Patterns

要旨　表面型大腸腫瘍性病変275病変を対象とし，pit patternからみた深達度診断について検討し，以下の結果を得た．①実体顕微鏡下pit patternの観察では，Ⅴ_Aの存在した病変は全例sm_2～3のsm深部浸潤を認め，Ⅴ_Iの存在した病変はm～sm深部浸潤するものがあり，Ⅴ_I，Ⅴ_A以外のpit patternから成る病変は粘膜内にとどまることが多く，粘膜下層へ浸潤していてもsm₁にとどまるものがほとんどであった．以上の点から実体顕微鏡下でのpit patternの観察は深達度診断に有用であり，特にⅤ_Aの存在はsm深部浸潤を確信してよいものと考えられた．②メチレンブルー染色後の拡大内視鏡を用いたpit patternの観察は，病変全体のpitの描出率が不良である点，実体顕微鏡下で観察されたpit patternとの一致率が低値である点から，現段階では深達度診断に有用でないと考えられた．

　The diagnosis of the depth of invasion by pit patterns was evaluted on 275 lesions of the superficial type of colorectal tumor, and the conclusions were summarized as follows : 1) Observation of pit pattern by stereomicroscopic examination showed that all lesions with Ⅴ_A pit pattern accompanied sm_2～3 invasion, and lesions with Ⅴ_I pit pattern would have m to sm invasion. Many lesions without Ⅴ_I or Ⅴ_A pit patterns remained within the intramucosal invasion, even when they accompanied sm invasion, most of them were limited within the sm₁ invasion. Therefore, pit pattern observation by stereomicroscope was useful for diagnosis of the depth of invasion, especially the existence of Ⅴ_A pit pattern indicated sm invasion. 2) Pit pattern observation with methylen blue dye spraying method by magnifying endoscopic examination may not be useful for diagnosis of the depth of invasion of superficial type of colorectal tumor at this moment, because it was not easy to observe pit pattern of the whole lesion and there was a discrepancy between the results observed by stereomicroscope and those by magnifying endoscopic examination.