直腸MALTリンパ腫の1手術例

Primary Mucosa-associated Lymphoid Tissue (MALT) Lymphoma of the Rectum, Report of a Case

要旨　直腸原発MALTリンパ腫の1切除例を経験した．患者は48歳の女性．主訴は下血．下部消化管内視鏡検査で肛門縁から5cmの部に隆起性病変を認め，生検にてMALTリンパ腫が疑われ，低位前方切除，D₂リンパ節郭清を施行した．組織学的にはcentrocyte-like cellの浸潤増殖を認め，MALTリンパ腫と診断した．腫瘍細胞は壁全層性に外膜結合織まで達し，直腸傍リンパ節に転移を認めた．MALTリンパ腫は長期間局所にとどまり予後良好と言われているが，壁深達度が固有筋層を越えて深く浸潤している場合には，リンパ節転移の可能性もあり，QOLを考慮しながらも進行直腸癌に準じたリンパ節郭清を伴う切除を選択すべきと思われた．

　We report a case of primary rectal mucosa-associated lymphoid tissue (MALT) lymphoma. The patient, a 48-year-old woman, presented bloody stool, and endoscopy revealed an elevated lesion on the lower rectum (Rb). Results of an endoscopic specimen biopsy suggested MALT lymphoma. Lower anterior resection with dissection of the regional lymph nodes was performed. Pathological examination showed that the tumor was composed of a proliferation of centrocyte-like cells, leading to the diagnosis of MALT lymphoma. The tumor had invaded the surrounding fatty tissue and the pararectal lymph nodes were involved.

　The progression of MALT lymphoma is thought to be slow, but, when tumor has invaded beyond the muscularis layer, it can be regarded as advanced rectal cancer and operation with lymphadenectomy should be performed.