The clinical and genetic manifestations of hereditary nonpolyposis colorectal carcinoma

Background Hereditary nonpolyposis colorectal cancer (HNPCC) is a syndrome that affects a significant percentage of the total cancer population but is not easily recognized because of a lack of a distinctive clinical marker such as multiple polyps. Data sources The present review discusses the clinical characteristics, pathology, genetics, management, and surveillance of HNPCC. The diagnosis of HNPCC is dependent upon family history. It is defined by the Amsterdam criteria consisting of: (1) 3 or more relatives with histologically verified colorectal carcinoma, 1 of whom is a first-degree relative of the other 2;(2) colorectal carcinoma involving at least two generations;and (3) one or more colorectal carcinoma cases diagnosed at less than 50 years of age. Conclusions The diagnosis of HNPCC requires the demonstration of vertical transmission of the syndrome in the family pedigree. Attention should be focused on reports of cancer of all anatomic sites and the determination of site, histology, and age at diagnosis.