大腸腫瘍の拡大観察―何が進歩したのか―V型pit pattern診断の変遷と現状―癌の深達度診断を中心に

Changes of V Type Pit Pattern Diagnosis for Colorectal Neoplasia and Its Present Status

要旨　V型pit patternは癌に特徴的なpit patternとして提唱されたが，その細分類の命名や定義にわかりにくい部分があった．2001年に工藤・鶴田らの合意により，V型pit pattern細分類の命名はVI型・VN型に統一された．その後，各施設によってVI型・VN型の定義が微妙に異なっていたが，2004年4月の“箱根pit patternシンポジウム”でVN型の定義が明確になされ，VN型pit patternは深達度診断におけるSM高度浸潤の確実な指標となった．その結果，VI型にM癌とSM軽度浸潤癌・SM高度浸潤癌すべてが含まれることになり，それらを鑑別するためのVI型pit patternの解析が盛んに行われている．一方，最近NBI拡大観察などの微小血管診断学も解析に導入されるようになり，より精密な早期大腸癌の質的診断が模索されており，今後のさらなる拡大内視鏡診断学の発展が期待される．

　V type pit pattern was proposed as a characteristic feature of early colorectal cancer, however, there had been confusion regarding the definition and naming for its subclassification. In 2001, in accord with the agreement between Kudo and Tsuruta, the naming of V type pit pattern subclassification was unified as VI and VN. Subsequently, in April, 2004, the clear criteria of VN type pit pattern was defined at the Hakone pit pattern symposium, showing that VN type pit pattern is a specific indicator for submucosal massive invasive colorectal cancer. As a result, cases with VI type pit pattern include various early cancers, such as mucosal, shallow ＆ deep submucosal invasive cancer. At present, detailed analysis on VI type pit pattern has been carried out in order to distinguish mucosal, shallow ＆ deep submucosal inavsive cancer. On the other hand, recently, new diagnostic modalities, such as endoscopic microangiology using narrow band imaging (NBI) magnification, have been applied to the more detailed endoscopic observation. Development of endoscopic magnifying diagnosis for clinical practice is expected, using these new modalities in the future.