大腸DLBCL—大腸癌との鑑別を中心に

Colorectal Diffuse Large B-cell Lymphoma, Report of Two Cases

要旨●大腸DLBCLは潰瘍型を呈するものが多く，中でも狭窄型の症例は大腸癌との鑑別が問題となることがある．大腸DLBCLと大腸癌の鑑別には検体検査所見においては腫瘍マーカー，造影CT所見では腫瘍内貫通血管所見が有用である．X線，内視鏡的には周堤様隆起や潰瘍の形状や壁伸展性，拡大内視鏡所見では上皮性変化を疑うような表面微細構造の異常や血管走行異常の有無により鑑別可能なことが多い．本稿では辺縁に腺腫性ポリープがありX線造影所見で大腸癌との鑑別が問題となった症例と，狭窄のため通常内視鏡検査による潰瘍部の評価が困難でX線造影所見が診断に有用であった症例を提示し，進行大腸癌との鑑別診断について言及した．

　DLBCL（Diffuse large B-cell lymphoma）of the large intestine often presents as an ulcerative type, and the stenotic type may be difficult to distinguish from colorectal cancer. Colorectal DLBCL can be differentiated from colorectal cancer by the presence of tumor markers in laboratory tests and intratumor penetrating vessels in contrast-enhanced computed tomography, by the shape of randwalls and ulcers and by overall extensibility in radiological and endoscopic examinations. In many cases, they can be distinguished by their shape, overall extension, and magnified endoscopic findings. In this report, we present two cases of colon DLBCL：case 1, an adenomatous polyp with marginal adenomatous polyp that was difficult to distinguish from colorectal cancer on radiological findings ; type 2 advanced cancer with an SMT-like randall ; and type 4 advanced cancer similar to case 2, in which radiological findings were useful for diagnosis because evaluating the ulcer site using conventional endoscopy was difficult because of strictures.