胃・直腸MALTリンパ腫の1例

Mucosa-associated Lymphoid Tissue Lymphomas of the Stomach and Rectum

要旨　患者は60歳代，女性．便潜血陽性の精査にて直腸に腫瘤を指摘され当院に紹介となった．下部内視鏡検査にて直腸に25mm大の粘膜下腫瘍様の病変を認め，対側には20mm大の表面平滑な丈の低い隆起性病変を伴っていた．上部内視鏡検査では胃体部に褪色調の微小陥凹が散在していた．生検病理組織所見から，いずれもMALTリンパ腫と診断した．全身検索にて病変は胃と直腸に限局していたため，臨床病期Stage I（Lugano国際会議分類）と診断した．H. pylori除菌療法を施行するも直腸病変の増大を認め，リツキシマブ単剤による2次療法を施行した．8クール終了後に直腸病変はほぼ消失，胃，直腸ともに病理学的寛解を得た．

　A 60-year-old woman was admitted to our hospital for further examination of a rectal tumor which had been investigated by colonoscopy for positive fecal occult blood. Colonoscopy revealed a submucosal tumor in the rectum, measuring 25mm in diameter.

　On the opposite side of the rectum, there was a flat elevated lesion, measuring 20mm in diameter. Upper gastrointestinal endoscopy revealed minute depression areas in the gastric body. Histological findings of the biopsy specimens from both the rectal and stomach lesions revealed mucosa-associated lymphoid tissue lymphoma. Systemic examination revealed no other infiltration of lymphoma cells and the lesions were localized to the primary sites, so this patient was diagnosed as Stage I. Helicobacter pylori eraducation therapy was attempted in this patient, but no remarkable effect was recognized in the endoscopic findings. Therefore, she was administered rituximub therapy as a second therapy. Endoscopic findings after 8 courses of rituximub therapy revealed remarkable regression of the rectum lesions, and histological findings of biopsy specimens from both the rectum and the stomach revealed disappearance of lymphoma cells.