多発大腸癌を合併した潰瘍性大腸炎の1例

Multiple Carcinomas of Colon and Rectum Complicating Ulcerative Colitis, Report of a Case

　潰瘍性大腸炎の癌化率は欧米では3％程度¹⁾と言われているが，本邦での報告例はいまだ少なく，1981年7月の第15回大腸癌研究会の全国集計²⁾では潰瘍性大腸炎1,416例中癌発生と関係したと思われる症例は11例（0.78％）にすぎない．われわれは全経過5年の短期間に大腸癌と前癌病変の多発をみた潰瘍性大腸炎の手術，剖検例を経験し，摘出大腸を全割して組織学的に詳細な検索ができたので，文献的考察を加えて報告する．

　A 29-year-old woman was admitted to Yokohama National Hospital in 1976 with a complaint of frequent mucobloody stool for the past one year. Barium enema studies revealed typical findings of ulcerative colitis. Prednisolone and salicylazosulfapyridine were administered under the diagnosis of active total colitis. During five years after initial attack she passed on her clinical course with remission and relapsing of symptoms. In April 1980, she was admitted to our hospital for operative therapy of colitis because of medical intractability.

　On admission severe anemia, left lower abdominal pain and perianal abscess were noted. Rectal biopsy showed epithelial dysplasia with marked small round cell infiltration in the lamina propria mucosa. Total proctocolectomy was done under the diagnosis of toxic megacolon on 20 th day of admission.

　Operative specimen revealed atrophic flat mucosa with two superficial ulcerative lesions at the cecum to the ascending colon, five polypoid neoplasms at the transverse colon, scirrhous neoplasm at the splenic flexure and six polypoid neoplasms mixed with villous overgrowth of mucosa at the descending colon to the rectum. Microscopic examination disclosed signet-ring cell carcinoma with marked vascular permeation in the scirrhous neoplasm and various type of invasive adenocarcinomas in all polypoid neoplasms and few foci of villous mucosa. These invasive carcinomas were surrounded by extensive or patchy lesions of various degree of epithelial dysplasia suggestive of precancerous change and intramucosal carcinomas. The epithelial dysplasia in the villous mucosa was characterized by histological transition from the flat colitic mucosa where cellular atypism had progressed downward from the upper part of tubules. The remaining mucosa showed atrophic colitis with Paneth cell metaplasia and fibrosis of submucosa.

　This case is a typical and rare example of multiple carcinomas and epithelial dysplasia based upon ulcerative colitis.