[Familial colorectal cancer. The Lynch syndrome].

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 the lack of a distinctive clinical marker such as multiple polyps. The authors present a clinical case of HNPCC sustained by clinical evolution, histologically and therapeutically verified. It has followed for 7 years, and related to the family pathological pedigree covering 3 generations. The case has been identified using the Amsterdam criteria, consisting in: (1) 3 or more relatives with histologically verified colorectal carcinoma, 1 of whom is a first-degree relative of the other two: (2) colorectal carcinoma involving at least two generations; (3) one or more colorectal carcinoma cases diagnosed at less than 50 years of age. The diagnosis of HNPCC requires the demonstration of vertical transmission of the syndrome in the family pedigree.