転移性大腸癌の形態学的特徴―X線像を中心として

Morphological Features of Metastatic Tumors of the Large Intestine―Analysis of Radiological Findings

要旨　転移性大腸癌178例を対象として，そのX線形態を中心に転移性大腸癌の形態学的特徴について検討した．原発巣は胃癌が126例と全体の2/3を占めていた．X線形態は従来の報告同様に収束型を呈するものが圧倒的に多数（74.4％）を占めたが，特殊例としてIIc様（胃原発1例），牛眼様（肺原発1例），巨大腫瘤様（腎原発1例）所見を呈する例もみられた．X線像のみからは原発巣を推定するのは困難なものが多かったが，病変数や転移部位などを加味すればある程度可能であり，他の疾患も含めた鑑別点について概説した．また，X線経過例からみると，浸潤が進行するに従い狭窄も高度となり，粘膜面には敷石状所見が出現してきていた．一方，内視鏡では表面に発赤，びらん，潰瘍を伴うものは生検にて転移の診断もある程度可能であった．ただし，X線にて軽度の収束像のみを呈する病変は内視鏡では病変の存在を指摘することも困難な場合が少なからず認められ，転移性大腸癌の診断のための大腸検査法としてはX線検査を第一に選択すべきと考えられた．

　One hundred-and-seventy eight cases of metastatic large intestinal tumors were analysed regarding tumor morphological features on barium enema. Two-thirds of all cases were metastatic tumors from gastric cancer. Radiologically, the most common finding was the tethered folds type (74.4％), which are considered characteristic of metastatic large intestinal lesions. However, there were a few specialized types as follows ; shallow depressed lesions resembling IIc type of early gastric cancer originating from the stomach (1 case), bull's-eye lesion originating from the lung (1 case), and huge mass lesion originating from the kidney (1 case). It was useful to analyse the morphological types, locations and the numbers of metastatic lesions for differential diagnosis of the primary sites and other diseases.

　According to the cases followed-up to more advanced stage by barium enema, stenosis of the affected lesions was characteristic of the more severe cases and mucosal surface with fixed transverse parallel folds developed into cobblestone appearance.

　On the other hand, from the endoscopic viewpoint, metastatic lesions with redness, erosion, and/or ulceration made possible to some degree the diagnosis of malignant tumors which could be verified later by biopsy. However, it was difficult for endoscopic examination to diagnose metastatic lesions which were detectable as slight tethered folds by barium enema. Therefore, we considered that barium enema was the first choice examination to diagnose metastatic tumors of the large intestine.