腹腔鏡補助下大腸切除術を行った横行結腸MALTomaの1例

A patient with a mucosa-associated lymphoid tissue lymphoma of the transverse colon treated by laparoscopy-assisted colon resection

◆要旨：患者は65歳の男性．便潜血反応陽性の精査目的で行った下部消化管内視鏡で横行結腸の脾彎曲部近傍に約2cmの0-IIa+IIc様病変を認めた．病理組織ではMALToma（mucosa-associated lymphoid tissue lymphoma）が疑われた．画像診断で遠隔転移は認めず，腫瘍の深達度は内視鏡下超音波検査で粘膜内に留まると診断された．2006年9月に腹腔鏡補助下横行結腸部分切除，D1郭清を施行した．病理組織学的所見ではリンパ節転移は認めず，粘膜内に限局したびまん性に異型リンパ球の浸潤がみられlymphoepithelial lesionも認めた．免疫染色で異型リンパ球のCD 20陽性だが，CD 3, CD 5, CD 10, cyclin D1はすべて陰性であった．以上から大腸MALTomaと診断した．2008年7月現在，再発を認めていない．大腸原発MALTomaはいまだ治療方針が定まっていない．今回の症例からは結腸MALTomaに対する腹腔鏡補助下結腸切除術は侵襲面のみならず，根治性の面からも有用な治療選択であると考えられた．

　We report a patient with mucosa-associated lymphoid tissue lymphoma（MALToma）of the transverse colon who underwent laparoscopy-assisted colectomy . A 65 year-old man who had a positive fecal occult blood underwent colonoscopy and was diagnosed as having MALToma of the transverse colon. Colonoscopy revealed a flat elevated lesion , 2 cm in diameter. Biopsy showed MALToma. No distant metastasis was detected by computed tomography, ultrasonography and positron emission tomography. Endoscopic ultrasonography showed the depth of the tumor invasion to be within mucosa. In September 2006, laparoscopy-assisted colectomy was performed. Postoperative pathological examination demonstrated diffuse atypical lymphocyte invasion to the mucosal epithelium（lymphoepithelial lesion）with no lymph node involvement. Also, immunohistochemical findings corresponded to MALToma. No recurrent disease has been recognized until March 2008. A guideline for the treatment of colonic MALToma has not been established yet. Laparoscopic surgery seems to be one of the treatment options for MALToma from the view point of radical resection as well as minimal invasiveness.