The relative risk of pancreatic cancer has been shown to be about 4 times that of the general population in familial adenomatous polyposis patients, but its frequency remains low, and the histological nature of these pancreatic tumors has been rarely reported. We describe the case of a 65-year-old patient, with a history of familial adenomatous polyposis coli, who developed advanced duodenal polyposis and a synchronous 25 mm tumor of the pancreatic isthmus. After total pancreatectomy and antrectomy, histological examination revealed an acinar cell carcinoma and duodenal adenomas with low and high-grade dysplasia, but no cancer. To our knowledge, this is the first description of the association of familial adenomatous polyposis with acinar cell carcinoma of the pancreas.