Crohn病の肛門部病変の肉眼・画像所見

Diagnosis of Perianal Lesions in Crohn's Disease

自験例Crohn病（CD）患者の73.6％（129例中95例）に肛門部病変がみられた．最も多かったのは痔瘻・肛門周囲膿瘍であり，76.8％を占めた．次いで裂肛36.8％，浮腫状skin tag 32.6％，肛門狭窄20.0％の順であった．Hughes分類ではprimary lesion 38.9％，secondary lesion 47.4％，incidental lesion 5.3％，primary lesionとsecondary lesionの合併8.4％であった．CDの肛門部病変は多発性，複雑性などの特徴があり，苦痛を与えないよう配慮すれば丁寧な視診，直腸指診，および内視鏡検査でその多くが診断可能である．痛みがある場合は麻酔下に行う必要があり，仙骨硬膜外麻酔が有用である．痔瘻・肛門周囲膿瘍の診断には肛門括約筋など解剖学的構造物との関係がよくわかるジャックナイフ位でのMRIが有用である．

　73.6％ of patients with Crohn's disease at our clinic have had perianal lesions. These lesions include perianal fistulas/abscesses（76.8％）, anal fissures（36.8％）, edematous skin tags（32.6％）, and anal strictures（20.0％）. According to Hughes' classification, 39％ of these lesions can be categorized as primary lesions, 47.4％ as secondary lesions, 5.2％ as incidental lesions, and 8.4％ as combined primary and secondary lesions. Multiplicity and complexity are characteristic properties of Crohn's perianal lesions. Most perianal lesions are accurately diagnosed by inspection, careful digital examination and meticulous endoscopy. EUA（examination under anesthesia）is necessary if the patient feels pain. Caudal epidural anesthesia may be an easy and safe procedure in an outpatient clinic. Modalities used for diagnosis and assessment of perianal fistulas include anorectal EUS, CT, and MRI. Jack-knife positioning MRI is best for imaging perianal fistulas because it shows the relationship of the fistula to the anal sphincter and other anatomical structures of the perianal region more clearly than anorectal EUS and CT.