Fig. 1

Imaging studies. a Ultrasonography showed that gourd-shaped hypo- and iso-echoic mass, 56 mm in size, was detected in the pancreatic head and body. b Enhanced computer tomography showed that solid well-circumscribed low-density mass, 7 cm in diameter, was located in the pancreatic head and body. c Heterogeneously enhanced mass was detected in the pancreatic body by gadolinium-enhanced MRI. d Endoscopic retrograde pancreatography (ERP) showed that main pancreatic duct was slightly deviated downward because of locoregional pressure effect, but direct invasion to the main pancreatic duct was not evident