新旧分類でのGroup 2病変の内視鏡再検，追跡結果の検討

A Follow-up of Group 2 Lesions According to the Old and New Classifications by Endoscopic Re-examination

要旨　当院では以前よりGroup分類は用いておらず，病理診断名が記載されており，再生異型，癌かの鑑別が困難な症例はatypical epithelium（以下，AE）と診断されており，新分類Group 2に相当する．2009年1月から2010年12月までにAEと病理診断された82例について検討を行った．生検施行例に占める割合は0.4％（82/18,930）であった．経過観察とともに再生検が行われた症例は70例あり，うち19/70例（27％）が胃癌と診断された．9例は再生検は施行せず，NBI拡大内視鏡所見のみで胃癌と診断しESDが施行されたがうち3例に胃癌を認めなかった．最終診断胃癌であった症例は33例（40％）であった．32/33例（97％）が分化型癌であり，うち5/33例（15.1％）に超高分化型癌がみられた．1か月後に経過観察が行われ，19/40例（48％）が癌であった．3か月後に11/32例（34％），6か月後に3/16例（19％）が癌であった．新分類Group 2に相当する病変の約半数程度は癌であり，約半数が炎症であった．NBI拡大観察は38/82例（46％）に行われ，正診できた症例は23/38（61％）であり，粘膜深層にのみ明らかな癌がみられた症例など診断困難例もみられた．

　Pathogenic diagnosis has been described without using the group classification in our hospital, and the term atypical epithelium（AE）has been used when it is difficult to differentiate between regenerative atypia and cancer. A total of 82 cases diagnosed with AE between January 2009 and December 2010 were examined. There were 70 cases that were followed-up with re-biopsy, and 19 of them were diagnosed with gastric cancer. Nine cases did not undergo re-biopsy and were treated by ESD because gastric cancer was diagnosed solely by magnifying endoscopy combined with NBI, in three of which gastric cancer was not observed. Gastric cancer was finally diagnosed in 33 cases（40％）. A follow-up examination one month later revealed gastric cancer in 19 of 40 cases（48％）. Gastric cancer was diagnosed in 11 of 32 cases（34％）three months later and 3 of 16 cases（19％）six months later. About half of lesions corresponding to Group 2 according to the new classification were likely to be cancer and a follow-up and re-biopsy were necessary. Magnifying endoscopy combined with NBI was carried out in 38 cases, of which 23 cases（61％）were diagnosed accurately, and some cases were difficult to diagnose.