盲腸・上行結腸の潰瘍性病変の診断―とくに肉芽腫性大腸炎（大腸Crohn病）を中心に

Diagnosis of Granulomatous Colitis: With special reference to value of fibercolonoscopy

　大腸に非特異性潰瘍を発生する疾患にはさまざまなものがあるが，このうち臨床的に問題となるのは主として原因不明のものである．ここでは，原因不明のもののうち主に盲腸・上行結腸をおかす肉芽腫性大腸炎granulomatous colitis（大腸Crohn病，Crohn's disease of the colon，全層性大腸炎transmural colitis）を中心に述べることにしたいと思う．

　すなわち，大腸に原因不明の非特異性潰瘍性病変を発生する疾患には潰瘍性大腸炎ulcerative colitisのほか肉芽腫性大腸炎，非特異性結腸潰瘍nonspecific ulcer of the colon，孤立性直腸潰瘍solitary ulcer of the rectumがある．しかし，これらの原因はいずれも不明であり，本態の異同については未解明の点が多く，潰瘍性大腸炎を除いては正確な診断は切除手術施行以前には一般に困難と考えられている．しかるに，最近結腸ファイバースコープが実用化された結果，右側結腸に発生した病変の診断は比較的容易となってきているので，ここでは，手術や剖検を行なったのちすべての情報にもとづいて最終診断を決定した潰瘍性大腸炎23例と肉芽腫性大腸炎12例についてその所見を比較検討するとともに，結腸ファイバースコープ検査とその直視下生検の，両疾患の鑑別に対する意義について考察を加えた．同時に，両疾患との鑑別を要する非特異性結腸潰瘍，intestinal Behçet，および腸結核の診断についても併せて考察を加えた．

　In order to clarify the significance of fibercolonoscopy in determining a diagnosis of granulomatous colitis, the pathological, radiological, endoscopic and clinical differences between granulomatous colitis and ulcerative colitis were investigated. Namely, observations were made on 12 cases of granulomatous colitis and 23 cases of ulcerative colitis, who had had colonic resections between 1954 and 1973.

　The findings noted lead to the diagnostic differentiation between the two conditions as follows: Granulomatous colitis is characterized by cobblestone-like or gyrous lesions distributed segmentally along the length of the bowel, without involving the rectum. The lesions of granulomatous colitis lack hemorrhage or suppuration, show a microscopic evidence of transmural inflammation and noncaseating granuloma formation, and are observed to have fissuring, probably an early stage of fistula, and stricture. The characteristic features also include negative tuberculin tests, diarrhea with no evidence intestinal bleeding, a palpable mass in the abdomen and involvement of the small intestine. In ulcerative colitis, by contrast, lesions are continuous and symmetrically distributed including the rectum. They either have a rough or granular surface or present features characteristic of pseudopolyposis, and show hemorrhage and suppuration. Inflammation is limited to the mucosa and submucosa with no evidence of noncaseating granulomas, fissuring, fistula or stricture. Blood in the stool and no involvement of the small intestine except backwash ileitis are also characteristic features of ulcerative colitis. As a consequence of assessments made of the various diagnostic techniques as to usefulness in differential diagnoses between the two disease states, it was noted that fibercolonoscopy and biopsy under direct vision with it applied in conjunction with the conventional procedures readily facilitate the differential diagnosis without any surgical intervention, in practically all aspects but the depth of inflammatory involvement. However, the depth of the inflamed lesion can also be estimated indirectly. It seems to follow that it is practicable to make the differential diagnosis between the two conditions even prior to colectomy, with the exception of atypical forms which present overlapping findings.

　Fibercolonoscopy is thus of remarkably great value in the diagnosis of granulomatous colitis insomuch as examination of the affected large intestine for appearance of lesions and to look for noncaseating granuloma formation can be accomplished only by this procedure combined with biopsy under direct vision.