2）内視鏡像からみた深達度診断②

Diagnosis of the Depth of Invasion of Colorectal Cancers from the Endoscopic Viewpoint

要旨　大腸早期癌の肉眼型とpit patternとの関連ではⅢs型pitは陥凹型に，またⅢL型pitは隆起型と平坦隆起型，およびLSTに，そしてⅣ型pitは隆起型と関連し，その組織学的特徴を反映した．また，V型pitはVA（amorphism）型とVN（non-structure）型に分けられ，病理組織所見における腫瘍腺管の構造異型や癌浸潤層の露出，異常間質の出現と関連し，主としてVA型pitはm・sm₁癌に，VN型はsm_2・3癌に対応した．更に，sm癌とmp癌の比較の結果，mp癌では有意にpit様構造は疎となり，また陥凹辺縁隆起においてVN型pitを呈する逆浸潤像が出現し陥凹境界線は断裂・複雑化した．以上から，大腸癌の診断学は通常観察から拡大内視鏡・pit pattern診断に至る一連の動的診断プロセスによって，病理組織診断に近い質的診断と深達度診断が可能となり，より適正な治療を選択できる段階へと発展したと考えられた．

　The result of study concerning macroscopic morphology and pit pattern in early colorectal cancers is as follows: Pit pattern Ⅲs is characteristic of the depressed type, pit pattern ⅢL is associated with the protruded type and the flat type, while pit pattern Ⅳ is associated with the protruded type. The pit pattern also reflects the histological diagnosis. Pit pattern V is divided into VA (Amorphism) and VN (Non-structure). The former corresponds to mucosal cancers and slightly invasive submucosal cancers (sm₁), whereas the latter corresponds to massively invasive submucosal cancers (sm_2,3). Moreover according to comparative studies of sm cancers (submucosal invasive cancers) and mp cancers (cancers invading the muscularis propria), the following facts are revealed: In case of mp cancers,“inverse invasion” those showing area pit pattern VN are detected more frequently on the elevated-margin of the depressed portion. As a result, the border line of the depression is demolished and becomes complicated. Considering the data mentioned-above, it is thought to be possible to distinguish sm cancers from mp cancers. Consequently, with observation leased on ordinary endoscopy combined with magnifying endoscopy (pit pattern diagnosis) the accuracy of diagnosis of colorectal cancers is thought to have been improved.