Imaging findings in pancreatic lymphoma: differential aspects.

When the radiologist is faced with a well-circumscribed tumoral mass in the pancreas, knowing when to direct the patient toward nonsurgical biopsy instead of surgical biopsy and staging is critical. Lymphoma does not require surgical staging or a palliative Whipple's procedure before chemotherapy or radiation therapy. A better overall prognosis with nonsurgical treatment is additional impetus to search for secondary signs of primary pancreatic lymphoma. In patients with primary pancreatic lymphoma, no marked pancreatic ductal dilatation is present even with ductal invasion. Adenocarcinoma commonly dilates the more distal pancreatic duct when more proximal ductal invasion has taken place. Lymph node involvement below the level of the renal veins was another finding not seen with adenocarcinoma. Clinical and imaging findings are otherwise not specific in the differentiation of pancreatic lymphoma and pancreatic cancer, but a bulky homogeneous tumoral mass without alteration of Wirsung's duct or the peripancreatic vessels should suggest the diagnosis. In patients with diffuse infiltration of the pancreatic gland without clinical signs of pancreatitis, the radiologist should be alert to the possibility of pancreatic lymphoma.