Helicobacter pylori除菌療法を行い消退した直腸MALTリンパ腫の1例

Regression of Mucosa-associated Lymphoid-tissue (MALT) Lymphoma of the Rectum after Eradication of Helicobacter pylori, Report of a Case

要旨　Helicobacter pyloriに対する除菌療法を行い消退した直腸原発のMALTリンパ腫の1症例を経験した．患者は67歳の女性．大腸癌検診で便ヒトヘモグロビン陽性を指摘された．大腸内視鏡検査で直腸下部(Rb)に径11mm大の隆起性病変を認めた．生検病理組織学的にはcentrocyte-like cellの浸潤増殖とlymphoepithelial lesionを認め，またサザンブロット法で免疫グロブリン重鎖遺伝子の再構成を認め，MALTリンパ腫と診断した．超音波内視鏡では第3層に主座を持つ低エコー腫瘤を呈した．胃のH. pylori陽性であったため除菌療法を行ったところ，除菌は成功し直腸MALTリンパ腫は次第に消退した．本治療は胃MALTリンパ腫のみならず直腸MALTリンパ腫にも試みるべき治療法と考えられた．

　We report a case of mucosa-associated lymphoid-tissue lymphoma of the rectum that regressed after eradication of Helicobacter pylori. A 67-year-old female was admitted to our hospital for further examination of a rectal polypoid lesion. Colonoscopic examination revealed a broad-based protrusion in the rectum (Rb) resembling a submucosal tumor. Histopathological examination of biopsy specimens showed diffuse infiltration of centrocyte-like cells, which were positive for L26 immunostaining and also formed lymphoepithelial lesions. Southern blot analysis of the specimen detected gene rearrangement of immunoglobulin heavy-chain (IgH). H. pylori was shown to be positive by rapidurease test, culture, and histological examination of biopsied gastric mucosa. Eradication therapy for H. pylori was successfully carried out. Colonoscopic examination 6 weeks after the end of the treatment showed marked regression of the rectal tumor. Almost complete regression was further confirmed by colonoscopy 33 weeks after the treatment.