非ステロイド系抗炎症剤（NSAID）起因性腸炎の病理組織学的特徴と鑑別診断

Histologic Features of Non-steroidal Anti-inflammatory Drug (NSAID)-Induced Colitis

要旨　非ステロイド系抗炎症剤（non-steroidal anti-inflammatory drug；NSAID）起因性腸炎16例について，臨床像から潰瘍型（10例），大腸炎型（3例），終末回腸炎型（3例）に分類し，生検組織像の特徴を解析した．また，外科的に切除されたNSAID起因性小腸横隔膜症1例の組織像も併せて解析した．組織学的に，非特異性炎型（潰瘍型9例，終末回腸炎型3例），虚血性腸炎型（潰瘍型1例），出血性腸炎型（大腸炎型2例），好酸球性腸炎型（大腸炎型1例）に大別された．横隔膜症が非特異性炎型（潰瘍型）に1例含まれており，小腸横隔膜症との組織学的類似性より横隔膜症は潰瘍型の治癒過程における特殊型であると思われた．非特異性炎型では潰瘍周囲の粘膜上皮の障害と炎症の程度は軽度であるにもかかわらず核分裂やアポトーシス小体が散見されるという特徴的な像を呈し，潰瘍発生にアポトーシスが重要な役割を果たしていることが示唆された．各病理組織型とも基本的像は異なるが一部重複する部分もあり，それぞれの発生機序の違いとともにそれらの多様性も示唆された．

　We reviewed the histologic features of non-steroidal anti-inflammatory drug (NSAID) -induced colitis, using biopsy specimens from 16 cases. Clinically, they were divided into three types ; ulcerative-type (10 cases), colitis-type (3 cases) and ileitis-type (3 cases) . In addition to them, a surgical case of ileal diaphragm disease was also evaluated. Histologically, they were classified as non-specific enteritis-type (12 cases), ischemic enteritis-type (1 case), hemorrhagic enteritis-type (2 cases) and eosinophilic enteritis-type (1 case) . Diaphragm disease was considered to be a special form of non-specific enteritis-type, histologically (or ulcerative-type clinically).

　In spite of mild inflammation and mild epithelial damage, mitotic figures and apoptotic bodies are occasionally seen in non-specific enteritis-type. It is suggested that apoptosis plays an important role in ulcer formation of NSAID-induced enteritis. Every type essentially had a different histologic features, which suggests different mechanism in each of them. However, they shared some features which indicates that the mechanisms of each type might be complicated by overlapping.