Adenoma and adenocarcinoma of the ampulla of Vater are uncommon neoplasms of the gastrointestinal tract that are found with increased frequency in familial adenomatous polyposis syndrome (1-3). Ampullary adenoma represents the precursor lesion to adenocarcinoma, and a coexistent adenoma can be identified frequently in patients with ampullary adenocarcinoma (1, 2). Because of their premalignant nature, ampullary adenomas are often resected either by polypectomy or, in the case of larger lesions, by pancreaticoduodenectomy (1,4,5). An association between adenomas of the ampullary region and pancreatic intraductal neoplasia has not been documented previously. Adenocarcinoma of the pancreas is often associated with pancreatic intraductal neoplasia (PanIN), which is thought to represent the precursor lesion for this cancer (6 -12). Several case reports documenting progression of high-grade (HG) PanIN to invasive pancreatic adenocarcinoma over time (17 mo to 29 y) support the role of PanIN as a precursor of carcinoma (10,13,14).The relationship between ampullary adenoma and PanIN has not been investigated previously, and only one analysis of the relationship between