Background: We retrospectively analyzed the endoscopic ultrasonographic characteristics of intraductal papillary tumors of the pancreas and identified signs indicative of malignant tumors.
Methods: Twenty-eight patients with intraductal tumors and 38 with other pancreatic cystic lesions underwent endoscopic ultrasonography, conventional ultrasonography, and endoscopic retrograde cholangiopancreatography (ERCP).
Results: Intraductal tumors were classified into three subtypes, and endoscopic ultrasonographic characteristics were assessed. In main duct type tumors, the main pancreatic duct showed a segmental or diffuse moderate-to-marked dilatation, often associated with intraductal nodules. Pancreatic parenchymal atrophy was frequently recognized. Branch duct type tumors consisted of multiple 5 to 20 mm cysts with the appearance of a cluster of grapes. The main duct was mildly dilated or nondilated. Combined type tumors had features of both main duct and branch duct types. Endoscopic ultrasonography (92%) differentiated pancreatic cystic lesions more precisely than ultrasonography (82%) and ERCP (89%). Main duct or combined type tumors, large tumors (> or = 30 mm for branch duct type), marked dilatation of the main pancreatic duct (> or = 10 mm for other types), and mural nodules suggested malignancy. Endoscopic ultrasonography demonstrated these signs more accurately than ultrasonography or ERCP.
Conclusion: Endoscopic ultrasonography is useful for diagnosing intraductal papillary tumors, particularly for predicting malignancy.