炎症性腸疾患の画像所見と鑑別診断—アフタ/びらんを主体とした病変

Endoscopic Features of Bowel Diseases that Present Aphthae and Erosions

要旨●アフタ，びらんは腸管のさまざまな疾患で生じうるため，その内視鏡的特徴の把握が診断に重要となる．Crohn病の初期像ではそれらが縦列するのが特徴である．アメーバ性大腸炎は盲腸，直腸に好発する白苔を伴うたこいぼ状潰瘍を呈する．診断には組織生検，便塗抹検査が必要である．クロストリジウム・ディフィシル腸炎は発赤，びらん，潰瘍，偽膜を来すのが特徴であるが，偽膜のない症例では内視鏡所見のみで診断は困難である．NSAIDs起因性腸病変は潰瘍型と腸炎型に大別され，さらに潰瘍型は膜様狭窄を合併することもある．病理組織像は陰窩のアポトーシスや好酸球浸潤が特徴であるが，生検のみで診断できない場合は，他疾患の除外や薬剤内服歴の聴取，薬剤中止後の改善所見の確認が重要となる．

　Since aphthae and erosions occur in various diseases, it is important to understand their endoscopic characteristics for diagnoses. The early lesions of Crohn's disease are characterized by tandem alignment. Amebic colitis is characterized by the appearance of octopus-like ulcers with white moss that often develop in the cecum and rectum. Endoscopic biopsies and stool smears are required for diagnosis. Clostridioides difficile infection is characterized by redness, erosion, ulcers, and pseudomembranes, but in cases without pseudomembranes, it is difficult to diagnose using endoscopic findings alone. NSAID-induced enteritis is typically classified into ulcer-type and enteritis-type, and the ulcer-type may be complicated by membranous stenosis. Further, histopathological images may be characterized by crypt apoptosis and eosinophil infiltration, making diagnosis difficult using biopsy alone. Therefore, it is important to take a detailed history of prescribed medicines and comorbidities and to confirm if there is patient improvement following discontinuation of the drug.