Abstract
Background. The hereditary flat adenoma syndrome (HFAS) is characterized by an autosomal dominantly inherited predisposition to multiple colonic adenomas (usually less than 100) with proximal predominance and flat as opposed to polypoid growth. Patients with the syndrome experience colorectal cancers in excess, and the lesions are distributed randomly in the colon. The polyps occur at a later age (median, 55 years) compared with age at onset of polyps in patients with familial adenomatous polyposis (FAP) and patients with the Lynch syndromes. FAP and HFAS are linked to the same locus on chromosome 5q21-q22. Methods. Upper endoscopic examination was performed on 22 relatives from four families with HFAS. Results. Fifteen patients from three of these families had multiple fundic gland polyps; four had duodenal or gastric adenomas. Periampullary carcinoma was present in two members from separate families. Conclusions. The authors conclude that the upper gastrointestinal tract pathologic characteristics of HFAS are similar to those described in FAP. Thus, those at risk for HFAS require upper endoscopic screening in addition to meticulous attention to the colon.