腸管悪性リンパ腫の鑑別診断―臨床の立場からみた診断上の留意点

Differential Diagnosis of Gastrointestinal Malignant Lymphoma Based on Clinical Viewpoints

要旨　腸管には中胚葉由来で，生体防御の役目を持つリンパ装置が数多く存在する．これらのリンパ装置は，また全身のリンパ節とも関連し合っているため，腸管の悪性リンパ腫では癌に比して多発しやすく，病態と病像も多彩である．この多発性，多彩性を理解するために，腸管のリンパ装置の解剖・生理について述べ，次いで悪性リンパ腫の分類の病期診断，検査と診断上の留意点につき概説した．これを踏まえて，多発性・びまん性の腸管の悪性リンパ腫に類似した形態を示し，鑑別診断上で問題となる疾患（びまん性リンパ濾胞増生症，偽膜性腸炎，アメーバ赤痢，Yersinia腸炎，immunoproliferative small intestinal disease，AIDS，mucosal prolapse syndrome）について，形態的な鑑別点を主体に述べた．

　The gastrointestinal tract abounds in lymph apparatus of mesodermal origin, which plays an important role in self-protection. These lymph apparatus are closely related to lymph nodes in the rest of the body. This fact explains the higher frequency of multiple occurrence as well as more protean pathophysiology and clinical manifestation in malignant lymphoma compared with cancers of the gastrointestinal tract.

　In order to understand these characteristics of malignant lymphoma, review was made on the anatomy and physiology of lymph apparatus followed by the classification and staging diagnosis as well as important points in work-up and diagnosis.

　Then crucial points were cited in differentiating such diseases with structural resemblance to multiple and diffuse malignant lymphoma as diffuse folliculosis, pseudomembraneous colitis, amebiasis, Yersinia colitis, immunoproliferative small intestinal disease, AIDS, and mucosal prolapse syndrome.