대한대장항문학회

Hereditary nonpolyposis colorectal cancer(HNPCC) is the most common ident fiable<br>risk factor of colorectal adenocarcinoma in patients under age 50.(approximately 5 to<br>subcategories of total colorectal cancer burden ). HNPCC syndrome may be divided into<br>two subcateories;(a) Lynch syndromeⅠ-hereditary site specific colon cancer,<br>and(b)<br>Lynch syndrome Ⅱ-colon cancer associated with other forms of cancer, particularly<br>endometrial and ovarian carcinoma. Because HNPCC is diagnosed only by family history,<br>minimum criteria of HNPCC was suggested by International Collaborative Group on<br>HNPCC. Minimum criteria is that(1) at least three relatives should have histologically<br>verified colorectal cancer: one of them should be a first degree relative to the other two,<br>familial adenomatous polyposis should excluded, (2) at least two successive generation<br>should be affected, (3) in one of the relatives colorectal cancer should be diagnosed<br>under 50 years of age. HNPCC syndromes have several cardinal feature, (1) proximal<br>colonic involvement (2) increased incidence of synchronous or metachronous lesion, (3)<br>early age of onset, (4) autosomal dominant qenetic transmission and (5) a better<br>prognosis when compared with the sporadic counterpart. Decision of surgical<br>management is based on these fectures. In HNPCC syndrome, a subtotal colectomy is<br>recommened as opposed to conventional right, left, or sigmoid resection, In Lynch<br>syndrome Ⅱ, prophylactic treatment must be considered for extracolonic organs,<br>especially the female genital tract. We report one case of hereditary<br>nonpolyposis<br>colorectal cancer with references.<br>