非腫瘍性胃RLHと胃MALTリンパ腫の経過観察例の検討―Helicobacter pyloriとの関連を中心に

Serial Changes of Radiographic, Endoscopic and Histological Findings in Reactive Lymphoid Hyperplasia (RLH) and Mucosa-associated Lymphoid Tissue (MALT) Lymphomas of the Stomach: Association with Helicobacter pylori Infection

要旨　長期にわたる経過観察の結果，低悪性度胃MALTリンパ腫と診断された8例（観察期間1～10年，初回検査時7例でH.Pylori陽性）と，経過観察中の非腫瘍性胃RLH7例（観察期間1～8年，初回検査時全例H.Pylori陽性）を対象とし，経過中のX線，内視鏡像と生検標本上のリンパ腫病変の変化およびH．Pyloriの菌体量の変化を比較検討した．両群間で観察期間に差はなかったが，低悪性度MALTリンパ腫群のほうが若年で男性が多い傾向を認めた．低悪性度MALTリンパ腫では，内視鏡像の改善はみられず，病理組織像の悪化が認められたが，経過中に7例で病変部のH．Pylori菌体量の減少あるいは自然消失が認められた．一方，非腫瘍性RLHでは，H.Pyloriは持続感染し，内視鏡および組織所見は経過中に明らかな進展を認めなかったが，除菌治療（5例で施行）後には内視鏡所見の改善を認めた．以上から，H.Pylori感染は非腫瘍性RLHとの間に強い関連性を有するが，MALTリンパ腫の発育，進展には直接関与しないことが示唆された．また，深部浸潤を来した低悪性度MALTリンパ腫は，少なくともその前段階の，表層浸潤にとどまり，除菌治療に反応する非腫瘍性RLHとは明確に区別されるべきと考えられた．

　We compared serial endoscopic and histological changes between eight patients with low grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma and seven patients with non-neoplastic lymphoid hyperplasia (so-called RLH) during followed-up priods ranging from one to ten years, in association with Helicobacter pylori (H. pylori) infection. Followed-up periods were almost equal between the two groups, but patients with low grade MALT lymphoma were relatively younger and tended to be predominately male. H. pylori infection was comfirmed by biopsy specimens in seven RLH patients and seven low grade MALT lymphoma patients at the first endoscopic examination.

　In patients with low grade MALT lymphoma, endoscopic and histologic grades gradually worsened during the follow-up period, while H. pylori histologically diminished or disappeared in seven patients without eradication treatment.

　All of the MALT lymphoma patients were finally treated with surgical gastric resection because of deep layer infiltration and lymph node involvement. In RLH patients, on the other hand, endoscopic and histologic grades did not advance despite continuous H. pylori infection. Five RLH patients were successfully treated with H. pylori eradication.

　These results suggest that H. pylori infection relates strongly with RLH or chronic gastritis, but transformation and development into MALT lymphoma may require some factors other than H. pylori infection. Low grade MALT lymphoma, especially one with deep layer infiltration (over the bottom of the submucosa), should be clinically separated from RLH, in which H. pylori eradication is effective.