虫垂・盲腸Crohn病の病理学的特徴と鑑別診断

Morphological Features and Differential Diagnosis of Crohn's Disease Limited to the Appendix and Cecum Adjacent to the Appendiceal Orifice

要旨　虫垂開口部の盲腸に敷石像（＋炎症性ポリポーシス）を有する9例はいずれも腫瘍と術前診断されていたが，病理学的にはCrohn病（CD）確診6例，CD疑診3例であった．盲腸CDのほとんどは虫垂CDに続発するのではなく，虫垂・盲腸に同時発生した病変と推定された．肉芽腫性虫垂炎と診断された11例のうち，リンパ球集簇巣から成る全層性炎，非乾酪性類上皮細胞肉芽腫，これらによる壁肥厚の所見から原発性虫垂CDと診断されたものが3例，一見，正常に見える虫垂に非乾酪性類上皮細胞肉芽腫が（多数）出現し，CDが疑われた2例，残りの6例は急性虫垂炎や虫垂の急性憩室炎に1～6個の肉芽腫が出現したものであった．原発性虫垂CDは小腸や大腸型CDと同様の特徴的組織像を呈しており，敷石像を呈する盲腸CDを合併することがわかった．

　Aims : To clarify the morphological features of Crohn's disease (CD) limited to the appendix and cecum adjacent of the appendiceal orifice, and the differential diagnosis among granulomatous lesions of the appendix.

　Materials : Nine cecal lesions showing a cobblestone appearance admixed with or without inflammatory polyposis (Table 1), and eleven cases with granulomatous appendicitis (Table 2).

　Results : Nine cecal lesions were preoperatively diagnosed as tumor in all, but, pathologically, 6 of them were definite CD and 3 of them were suspected CD. The definite CD showed transmural lymphoid aggregates, non-caseating epithelioid cell granulomas, and fissures. However, the suspected CD showed mild transmural inflammation, and multiple fissuring scars, but no granulomas. The cecal CD had appendiceal CD simultaneously. Out of 11 cases of granulomatous appendicitis, two (Case 2-9～11 in Table 2) were diagnosed as definite CD by the similar histology to that of intestinal CD of another part of the intestine. Two were diagnosed as suspicious CD because of the presence of granulomas in the appendix with normal appearance (Case 2-7, 8 in Table 2), and in acute appendicitis with a f ew (1～6) granulomas.

　Conclusion : First, cecal CD has the macroscopic features of localized cobblestone appearance at the orifice of the appendix, and should not be misdiagnosed as cecal or appendiceal tumor. Second, primary appendiceal CD has microscopic features different from other lesions with granulomas, and should be discriminated from other granulomatous appendicitis.