Crohn病診断基準の問題点―病理の立場から生検における非乾酪性類上皮細胞肉芽腫を中心に

Problem in Diagnostic Criteria of Crohn's Disease

要旨　Crohn病254例の大腸および上部消化管のルーチン生検標本を用いて，本症の診断基準（改訂案）の主要所見に取り上げられている非乾酪性類上皮細胞肉芽腫（以下，肉芽腫と略）の検出（陽性）率を中心に，病理形態学的立場から検討した．肉芽腫陽性率は，初回生検では43.3％（大腸：33.9％，上部消化管：20.9％）であり，複数回生検を重ねると56.7％（大腸：42.1％，上部消化管：30.7％）と上昇した．また病変別には，大腸の活動期病変からの生検で最も陽性率（25.0％）が高かった．以上から，肉芽腫だけに依存する本症の生検診断には限界があることを指摘し，合わせてその診断率向上には類上皮細胞集団（cluster），組織球の小集簇巣，focally enhanced gastritisなど本症に特徴的組織所見を加味した診断基準が必要であると強調した．

　We investigated the incidence of positive epithelioid cell granulomas which is regarded as a main factor in the criteria for the diagnosis of Crohn's disease (preliminary proposal) using biopsy specimens taken from conventional upper gastrointestinal (GI) endoscopy and colonoscopy. The incidence of positive granulomas was 43.3% (colon : 33.9%, upper GI 20.9%) in the initial endoscopic examination. This increased to 56.7% (colon : 42.1%, upper GI 30.7%) after consideration and additional examination. In morphologically different endoscopic lesions, incidence was highest in biopsy specimens taken from active colonic lesions (25.0%) . In conclusion, we suggest that it is unreasonable to rely only on the detection of granulomas for the diagnosis of patients with Crohn's disease. In our view, the diagnosis should also include various morphological and histopathological findings, such as epithelioid cell cluster, microaggregates of histiocytes, and focally enhanced gastritis.