消化管疾患における肉芽腫の病理学的特徴と鑑別診断

Digestive Tract Diseases with Granulomas

要旨●肉芽腫の出現する主な消化管疾患として原因別に，①原因不明：Crohn病，サルコイドーシス，肉芽腫性胃炎，直腸リンパ球性ポリープ，虫垂炎，大腸憩室症，大腸癌，②感染症：結核，エルシニア腸炎，チフス，③異物反応：潰瘍性大腸炎（陰窩関連肉芽腫），ランタン沈着症，腸管気腫性囊胞症，虚血性腸炎，内視鏡切除後潰瘍，縫合糸肉芽腫，バリウム肉芽腫，④マクロファージの異常：慢性肉芽腫症，マラコプラキアなど，さまざまな疾患が存在する．肉芽腫は組織学的にサルコイドーシス型，結核型，偽結核型，異物型の4型に分類され，肉芽腫のみでもある程度は疾患の鑑別診断を絞ることができるが，疾患の活動性や時相により典型的な像を示さないこともある．病理組織検体において肉芽腫が検出された場合，本稿で取り上げた疾患を念頭に置き，臨床像を加味して総合的に鑑別診断を行うことが重要である．

　Digestive tract diseases with granulomas classified based on causes are as follows：①unknown cause：Crohn's disease, sarcoidosis, granulomatous gastritis, rectal lymphocytic polyp, appendicitis, colonic diverticulosis, and colon cancer ; ②infection：tuberculosis, yersiniosis, and typhoid fever ; ③foreign body reaction：ulcerative colitis（crypt-related granuloma）, lanthanum deposition disease, pneumatosis cystoides intestinalis, ischemic enteritis, ulcer after endoscopic resection, suture granuloma, and barium granuloma ; and ④disorders of macrophages：chronic granulomatous disease, marakopurakia, etc.

　Granulomas in digestive tract diseases are histologically classified into sarcoid, tuberculosis, pseudotuberculosis, and foreign body reaction types. The differential diagnosis may be suggested only by the histological features of granuloma in some cases ; however, the granuloma sometimes does not exhibit features typical of a specific disease in terms of the activity or time phase.

　If the granuloma is detected in pathological tissue specimens, it is important that a differential diagnosis takes into account the clinical picture, as well as the histological features of the granuloma.