びまん浸潤型癌と鑑別困難であった大腸Crohn病の1例

Crohn's Disease Hard to Differentiate from the Diffusely Infiltrating Type of Colon Cancer, Report of a Case

　大腸の炎症性疾患（以下IBDと略す）の中には原発性の大腸癌，特にびまん浸潤型癌¹⁾と鑑別が極めて困難な症例があり，診断，治療の決定に難渋する場合がある．本例は直腸に約8cmの長さにわたって狭窄があり，術前IBDとびまん浸潤型癌との鑑別に苦慮し，術後に直腸のCrohn病とされた興味ある症例であったので，若干の考察を加えて報告する．

症　例

患　者：37歳，男性，タイヤ販売修理業．

主　訴：便秘．

既往歴：4年前急性腸炎？　発熱，下痢，嘔吐で10日間入院．

家族歴：父親胃癌．

現病歴：1980年4月までは1日1回の便通を認めていたが，次第に便秘となり6月には下剤を服用しないと便通を認めなくなった．1ヵ月前からは粘液，血液が便に付着し，軽い下腹部痛を伴うようになった．発熱はみられず，体重減少は6カ月間に2kgであった．

　Segmental stenosis between the rectum and the sigmoid colon could be seen in inflammatory disease such as Crohn's disease and ulcerative colitis as well as diffuse invasive type of carcinoma, and their differential diagnosis is sometimes quite difficult. This case was one of such difficult cases and was finally diagnosed as Crohn's disease.

　The patient was 37 year-old man who came to our institution with six months' history of progressive constipation and blood in stool. Laboratory data disclosed elevated ESR, positive CRP and increased α₂-globulin but otherwise non-remarkable. However, radiologic and endoscopic examination revealed tubular stenosis of 8 cm long mainly at the rectum, serrated marginal change and cobblestone appearance without longitudinal ulcerations. Diffuse invasive carcinoma was strongly suspected and biopsy was performed three times but they were negative for carcinoma. There were no abnormalities in the stomach and the small intestine. Salicylazosulfapyridine was administerted for one month with a diagnosis of inflammatory disease, but no significant improvement was obtained and rectosigmoidectomy was performed between middle portion of the rectum and recto-sigmoid junction. Ileo-cecal resection was also performed because of adhesion and reconstruction of the colon was done by pull-through method.

　Macroscopic findings showed stenosis due to thickening of the wall and cobblestoning. Histological evaluation disclosed severe submucosal inflammation as well as transmural inflammation with fissuring. Furthermore, multiple non-caseating granulomas were found in every layer of the wall. At the terminal ileum, there were erosion, submucosal edema and proliferation of lymphoid follicles but it was hard to be considered as a skip lesion.

　Therefore, it was diagnosed as Crohn's disease of the colon although atypical, and the patient has been placed on salicylazosulfapyridine for over the last one year and nine months, and no recurrence has been noted so far. however, a long-term follow-up is important for this case.