APC and Familial adenomatous polyposis: The very recently described familial adenomatous polyposis (FAP)-HCA occurs in patients with germline mutations of the APC gene and shows also activation of the WNT signaling pathway as demonstrated by strong positivity for glutamine synthetase. Thus, this rare subtype shares features with B-HCA, but it does not reveal nuclear beta-catenin accumulation and an increased risk of malignant transformation has not been established for these HCA [11].