Imaging of uncommon tumors of the pancreas.

In this article, the radiological manifestations of a variety of uncommon tumors of the pancreas are illustrated, with emphasis placed on their appearance at helical CT. Islet cell tumors, because of their vascularity, typically present as masses that are hyperattenuating to the normal pancreas at dual-phase helical CT. Lymphomas appear as hypoattenuating focal lesions or can diffusely infiltrate the gland. Absence of biliary tree dilatation, despite the presence of a bulky tumor, or associated extensive retroperitoneal adenopathy should offer clues to the diagnosis. Pancreatic metastases are usually seen in patients with advanced cancers, although isolated metastases from renal cell carcinoma can occurs years after the original tumor; such patients may benefit from surgical resection. Finally, the appearance of some rare neoplasms of mesenchymal origin is discussed.