切除標本で“dysplasia”を認めた潰瘍性大腸炎の1例

Long-Standing Ulcerative Colitis with Epithelial Dysplasia Found in the Resected Specimen, Report of a Case

要旨　28歳（手術時）女性．全大腸炎型の潰瘍性大腸炎で，慢性持続型であったため発症後12年を経過した時点で手術が施行された．手術は左半結腸切除という潰瘍性大腸炎としては非定型的な手術方法であった．術後縫合不全を来し，再手術にて吻合部を切除し人工肛門を造設した．再手術時に切除された吻合部のわずかな直腸壁に，明らかな“dysplasia”を認めた．術後定期的に内視鏡下生検を施行した．残存直腸の炎症が難治性であり，また，内視鏡下生検による追跡では，持続性に炎症があるために癌を見逃す危険性もあると考えられたので，初回手術時から1年2か月後に残存直腸および結腸を切除した．切除標本にはdysplasiaや癌は認められなかった．

　A twenty-eight-year old woman patient with total colitis for 12 years was operated on because of the chronic continuation of the disease. Left hemicolectomy, which is an unusual procedure for ulcerative colitis, was performed because of the partly deficient external anal sphincter caused by a previous fistula operation. On the fifth post operative day, reoperation was performed because of anastomotic leakage. During the reoperation Hartmann's procedure was performed. A small piece of rectal wall around the anastomosis was removed and, histologically, it showed a definite high degree of epithelial dysplasia. Postoperatively, colonoscopy and biopsy were repeated to examine the residual rectum and the colon. Because of the continuous inflammation of the rectum and of the definite high degree of dysplasia in the rectal mucosa of the previous resected specimen, excision of the residual rectum and the colon was performed two years after the first operation. Histology of the resected specimen at this time did not show any evidence of epithelial dysplasia or carcinoma.

　In this case, epithelial dysplasia was thought to be present in flat mucosa, but histologically, dysplasia was present in the deeper half of the crypts. For this reason, it is considered that it would have been difficult to make a preoperative diagnosis of dysplasia even if biopsies had been taken from the right place.

　The indication for immediate surgery when epithelial dysplasia is first detected is a controversial subject. In this case, we finally decided to perform proctocolectomy, mainly because of the possible risk of our missing dysplasia or carcinoma in random biopsies taken from the continuously inflamed mucosa.