炎症性腸疾患の鑑別診断—病理学的アプローチ

Differential Diagnoses of Inflammatory Bowel Diseases：Pathological Approaches

要旨●炎症性腸疾患は，潰瘍の有無とその形態を主所見として，①縦走潰瘍型，②輪状潰瘍型，③円形潰瘍型，④炎症性ポリポーシス型，⑤浮腫・発赤・びらん型，⑥腫瘍様隆起型，に分類され，鑑別疾患が決定される．さらに，潰瘍辺縁の性状などの副所見を組み合わせることで鑑別疾患を絞り込むことができる．炎症性腸疾患の生検診断の役割は，臨床画像診断の整合性を確認することにある．そのためには，①炎症の時相判定，②粘膜傷害の原因推定，③特異的組織所見の検索，の3つの過程に沿った病理組織像の解析が必要である．潰瘍形成病変では，潰瘍辺縁（粘膜傷害の原因推定）と周囲粘膜（炎症罹患範囲の判定）および潰瘍底（病原菌や肉芽腫などの検出）からの生検が必須である．

　Inflammatory bowel diseases are classified primarily into the ①longitudinal ulcer type, ②circular ulcer type, ③round-oval ulcer type, ④inflammatory polyposis type, ⑤edema, redness, hemorrhagic, and erosions type, and ⑥tumor-like elevated type, based on the presence or absence of ulcers and their morphology. Furthermore, the differential diagnosis can be narrowed down by combining secondary findings such as the properties of the ulcer margin mucosa. The role of the biopsy diagnosis of inflammatory bowel disease is to confirm the consistency of clinical imaging. For that purpose, it is necessary to analyze the histological image along three processes as follows：（1）determining the phase of inflammation, （2）estimating the cause of mucosal injury, and（3）searching for specific histological findings. For ulcer-forming lesions, biopsy from the ulcer margin mucosa（estimation of the cause of mucosal injury）, surrounding mucosa（determination of the extent of inflammation）, and ulcer floor（detection of pathogens, granulomas, etc.）is essential.