Rare pancreatic malignancies.

The incidence of pancreatic malignancy in most countries is increasing, and the overall prognosis for nonendocrine pancreatic cancer is grim. The majority of nonendocrine pancreatic malignancies are duct cell adenocarcinomas with no special features. However, several morphologic subtypes have been fairly recently recognized and classified, some of which appear to have a different inherent biologic behavior and a chance for a longer survival after resection. This article describes the rare nonendocrine pancreatic malignancies, emphasizing those clinical, pathologic, and radiologic features that serve to differentiate these entities from the more common duct cell adenocarcinoma of the pancreas.