進行癌やそのほかの胃病変との鑑別が必要な胃悪性リンパ腫―X線診断を中心に

Radiological Diagnosis of Advanced Malignant Lymphoma of the Stomach which Needs Differential Diagnosis with Advanced Carcinomas and Other Diseases of the Stomach

要旨　胃の悪性リンパ腫（以下，ML）の正診率は多彩多発型では75％であったが，その他の肉眼型では正診と疑診を合わせても50％以下であった．したがって，MLの大多数の症例が，癌や粘膜下腫瘍，炎症などとの鑑別が必要であると考えられ，今回，進行MLの鑑別診断について，肉眼所見およびX線所見を検討した．その結果，潰瘍型と2型癌との鑑別では，① MLは潰瘍が不整形であってもなめらかな線で描出されること，② MLはX線で伸展不良が軽いことが，重要な鑑別点と考えられた．隆起型とGISTとの鑑別では，MLの軟らかさと隆起表面の散在性の微細な星芒状陥凹が鑑別に有用であった．巨大皺襞型とLP型胃癌との鑑別では，腫大皺襞の規則的蛇行の有無，潰瘍の形態，X線における伸展不良の程度により鑑別可能と思われた．また，MLはサルコイドーシスや梅毒などの胃炎との鑑別も問題になる．胃サルコイドーシスは前庭部に多い傾向があるが，病変の形態では鑑別困難であった．胃梅毒も病変が多彩であるが，各所見を詳細に検討すればMLとの鑑別は可能であると思われた．

　The diagnosability of the malignant lymphoma（ML）of the stomach was difficult except for varied type ML. We studied macroscopic（or endoscopic）and radiographic findings to clarify the differences between advanced ML and other diseases of the stomach. It is possible to differentiate Ulcerative type ML from Type 2 gastric carcinoma by radiographic findings because even if an ulcer is asymetrical in form in ML it is depicted in a smooth line and ML has the elasticity of the gastric wall. The differences between Protruded type ML and GIST are the elasticity of the gastric wall and the star-shaped slight depression on the surface of the protrusion of ML. Giant rugal type ML can be differentiated from Linitis Plastica type gastric carcinoma because of regularly tortuous swollen folds, features of ulcer and the elasticity of the gastric wall. It is also necessary to differentiate ML from gastric inflammatory diseases. However discrimination of sarcoidosis from ML is difficult except for the fact that in sarcoidosis the lesion is often involved in the gastric antrum. Gastric syphilis which also has various macroscopic findings can be differentiated from ML by review of the radiographic findings in detail.