The clinical and imaging spectrum of pancreaticoduodenal lymph node enlargement.

Pancreaticoduodenal lymph node enlargement, regardless of cause, has been a source of imaging confusion because of its propensity to mimic pancreatic malignancy yet not cause biliary obstruction. Thirty-eight patients with pancreaticoduodenal adenopathy were imaged with several methods. Pancreaticoduodenal lymphadenopathy could be distinguished from intrinsic pancreatic abnormality on only 44% (14/32) of CT scans and 54% (6/11) of sonograms. Demonstration of intact tissue planes separating adenopathy from pancreas and, to a lesser degree, extrapancreatic vascular displacement were the most helpful diagnostic signs. Surprisingly, 31% of patients had biliary obstruction. Care must be taken in distinguishing metastatic lymphadenopathy from primary pancreatic tumors. The presence or absence of jaundice should not be considered a helpful sign.