胃MALTリンパ腫除菌治療後の長期経過と予後―t(11；18)(q21；q21)転座とEUSを中心に

Long-term Follow-up Outcome of Gastric MALT Lymphoma after H. pylori Eradication with Special Reference to t(11 ; 18)(q21 ; q21)Translocation and Endoscopic Ultrasonography

要旨　胃MALTリンパ腫の病態はt(11;18)(q21;q21)転座（API2-MALT1キメラ遺伝子）の有無と除菌療法に対する反応性で3群（A，B，C群）に分類される．A群はAPI2-MALT1陰性でresponderの群，B群はAPI2-MALT1陰性でnon-responderの群，C群はAPI2-MALT1陽性でnon-responderの群である．その特徴は，A群はH. pylori陽性・深達度はSMまで・臨床病期がI期であり，長期にわたり再発を認めない．B群は深達度MP以深・臨床病期II1期以上・diffuse large B-cell lymphoma成分を有する例が多く，肉眼型は隆起型が目立つ．C群はH. pylori陰性・臨床病期II1期以上の例が多く，diffuse large B-cell lymphoma成分は認めず，肉眼型はcobblestone粘膜が特徴的である．API2-MALT1の検索とEUSによる進展度診断は除菌の反応性を予測する有用な手段である．

　Fifty-seven patients of gastric MALT lymphoma were treated by eradication therapy for Helicobacter pylori and followed up by endoscopy and biopsy. They were classified into 3 groups (Group A, B and C) according to their responsiveness to antibacterial treatment and positivity of t(11 ; 18)(q21 ; q21)translocation, namely API2-MALT1 chimeric transcript (API2-MALT1). Forty-two patients in Group A were responders which showed negative API2-MALT1. Five patients in Group B were non-responders which showed negative API2-MALT1. Ten patients in Group C were non-responders which showed positive API2-MALT1. In group A, characteristics were positive for H. pylori infection, whose tumor invasion was limited in the mucosa or submucosa with clinical stage I. In group B, the characteristics were invasion of the proper muscle or more with clinical stage II1 or more. The component of diffuse large B-cell lymphoma cells and the endoscopic feature of protruded type of tumor were often observed. In group C, the characteristics were negative for H. pylori infection, clinical stage II1 or more, neither diffuse large B-cell lymphoma cells component nor cobblestone mucosa of endoscopic features were present.

　Evaluation of clinical stage by EUS and detection of API2-MALT1 are useful to identify cases that may be responsive to H. pylori eradication therapy.

　1) Department of Gastroenterology, Aichi Cancer Center Hospital, Nagoya, Japan

　2) Department of Pathology, Nagoya City University Medical School, Nagoya, Japan

　3) Department of Pathology and Molecular Diagnosis, Aichi Cancer Center Hospital, Nagoya, Japan