Colorectal Cancer in FAP
Malignancy in Familial Adenomatous Polyposis: Untreated FAP patients develop colorectal cancer in 100% of cases usually by age 40 years. Malignant transformation has been reported as early as 9 years of age. On the other hand, cancer formation is delayed to around 50-55 years of age in attenuated FAP. The morphologic features and distribution of colorectal cancers in FAP are similar to the sporadic colorectal cancers; however, the frequency of multiple synchronous tumors is much greater (almost 48% of cases). The image shows one of the thousands of adenomatous polyps from a case of FAP.