大腸にmultiple lymphomatous polyposis（MLP）と類似の所見を呈した成人T細胞白血病/リンパ腫（ATLL）の1例

Adult T-cell Leukemia/Lymphoma with Severe Gastrointestinal Invasion, Especially Similar to the Appearance of Multiple Lymphomatous Polyposis in the Colon, Report of a Case

要旨　患者は57歳，男性．難治性下痢を主訴に釜石病院を受診し，血液検査で白血球の高値を指摘された．当院初診時，白血球数は171,500/μl，血清抗HTLV-I抗体は陽性で，LDHは461IU/lと高値を示した．末梢血，骨髄ともに腫瘍細胞が多数を占め，末梢血に典型的なflower cellを認め，成人T細胞白血病/リンパ腫と診断された．表在リンパ節腫大は認めなかったが，腹部USで肝門部リンパ節の腫大を認め，腹部CTでは胆囊床，門脈周囲にlow densityを認め腫瘍浸潤と考えられた．消化管X線・内視鏡検査では，胃に多発微小びらんを，小腸にはKerckring皺襞の著明な腫大と微小びらんを伴う不整粘膜像を認めた．特に大腸には，中心陥凹を伴う4～5mmの比較的均一な大きさの小隆起が散在性に多発して認められ，悪性リンパ腫でいうmultiple lymphomatous polyposis（MLP）と類似の所見を呈した．胃の微小びらん，および大腸の小隆起からの生検組織診において，non-Hodgkinリンパ腫（T細胞型）と診断された．以上から，本症例は胃，小腸，大腸に消化管浸潤を伴い，特に大腸においてMLPと類似の所見を呈した成人T細胞白血病/リンパ腫の1例と考えられた．

　A 57-year-old man was admitted to our hospital because of refractory diarrhea. Hemogram on admission showed that white blood cell count was high (171,500/μl) with abnormal lymphocytes (more than 90%) and serum LDH was elevated. Serum anti-HTLV-I antibody was positive. There was no superficial lymph node swelling. Radiographic examinations showed diffuse edematous large Kerckring's fold with fine irregular granular change and multiple minute erosions in the small intestine and multiple small polypoid lesions with central depression in the large intestine. By endoscopic examination many minute erosions were seen in the stomach and multiple small polypoid lesions with central depression in the colon. Histological examination of the biopsy specimens from the stomach and large intestine showed diffuse infiltration of abnormal lymphocytes into the mucosa and lamina propria mucosae. The nuclei were large and irregular-shaped. Immunohistochemical examination showed that infiltrating lymphocytes proved to be of T-cell phenotype. We thus diagnosed the patient as acute-type adult T-cell leukemia/lymphoma (ATLL) with gastrointestinal involvement. Gastrointestinal appearance in this case was caused by infiltration of ATLL tumor cells and especially that of the large intestine was similar to multiple lymphomatous polyposis (MLP). We reported this case with further discussion about the clinical and pathological appearance of the gastrointestinal lesions in ATLL.