Air in the main pancreatic duct associated with a pancreatic intraductal papillary mucinous neoplasm.

A 62-year-old man was referred to our hospital after ultrasonographic mass screening detected a pancreatic cyst that proved to be an intraductal papillary mucinous neoplasm. Computed tomography additionally demonstrated air in the main pancreatic duct. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography delineated a filling defect in the main pancreatic duct in the body of the pancreas. The sphincter of Oddi was open. The main pancreatic duct was dilated by viscous mucin; air in the duct was attributed to consequent dysfunction of the sphincter. Laboratory findings included no significant abnormality. The patient has remained asymptomatic during follow-up. Of 25 previously reported cases with air in the duct, only 1 involved an intraductal papillary mucinous neoplasm.