2)下部消化管

Radiological Diagnosis of Submucosal Tumor of the Lower gastrointestinal Tract

要旨　小腸の粘膜下腫瘍は，管腔内発育，壁内発育，管腔外発育の形態をとる．特に管外性発育を呈する病変の拾い上げ診断には，充盈像による圧迫が重要であり，陰影欠損やニッシェ（バリウム斑）を見つけだすことが拾い上げ診断に重要である．小腸の粘膜下腫瘍は腸重積の原因となる．大腸の粘膜下腫瘍は，大きさによって種々の形態を認める．その特徴は，①立ち上がりなだらか，②表面は正常粘膜に被覆され平滑，③bridging foldを伴う，④緊満したものが多い，⑤脂肪腫・リンパ管腫・粘液腫などは柔らかく形態が変化する．鑑別診断は，上皮性の癌や転移性腫瘍，子宮内膜症や炎症性腫瘤など多彩なものが含まれるが粘膜下腫瘍の特徴を見い出せば診断は容易である．

　Submucosal tumor of the small intestine shows three types of development ; intra luminal, inside of the wall and extracanal . In particular, in cases of a tumor's extracanal development it is difficult to detect such tumors by X ray study. It is important to detect these lesions which, when the canal is filled with barium, show themselves under compression by a defect in the wall or by barium spots. Submucosal tumor of the small intestine sometimes causes intussusception. Submucosal tumor of the colon is recognized under various forms by size. As for the characteristics, ① The start of the tumor is a gentle slope, ② The surface is coated by normal mucosa and is smooth, ③ Associated with bridging fold, ④ The surface of the tumor is stretched, ⑤ The shape of tumors such as lipoma, lymphangioma and mucocele are soft and changeable. Submucosal tumors should be differentiated from carcinoma, metastatic tumor, endometriosis, and tumors due to inflammation. However, they are not so difficult to diagnose if we detect the characteristics of submucosal tumor as outlined above.

　1) Department of Internal Medicine, Kitasato University East Hospital, Sagamihara, Japan