放射線腸炎との鑑別に苦慮した胃癌結腸転移の1例

A case of colon metastasis from gastric cancer difficult to distinguish from radiation enteritis

結腸転移は比較的まれな疾患であり^1），生検や腫瘍マーカー，¹⁸F-FDG PETで偽陰性を呈しやすく^2-4），診断は困難である^5）。類似した臨床経過や画像所見を示す放射線腸炎との鑑別については，造影CTが有用であると考えられる。今回，胃癌術後照射後に放射線腸炎との鑑別に苦慮した結腸転移の症例を経験し，結腸転移に典型的な画像所見を得たので若干の文献的考察を加えて報告する。

The occurrence of colon metastases is relatively rare and their imaging diagnosis is difficult. In this report, we describe a woman in her 60s who had difficulty differentiating radiation enteritis from colon metastasis. Four years after postoperative irradiation of a scirrhous gastric cancer, CT showed stenosis and an irregular wall contrast effect in the colon near the irradiated field. Because the contrast area of the bowel expanded over time, surgical resection was performed. Histopathological examination revealed colon metastasis from gastric cancer. The malignant target sign on contrast-enhanced CT is useful in differentiating radiation enteritis from colon metastasis.