Figure 1

Preoperative imaging diagnoses. A) Magnetic resonance imaging findings (axial, T2-weighted image). The image indicated by a rectangle is illustrated as an inset in the lower right. A black curved line in the illustration indicates the main pancreas duct (MPD). A cystic lesion, illustrated as a cluster of gray areas, is seen around the main pancreas duct. This lesion is a cluster of multiple dilated branch pancreas ducts (BPD) and has been diagnosed as branch intraductal papillary mucinous neoplasm. B) Magnetic resonance cholangiopancreatography findings. The image is illustrated as an inset in the lower right. Black lines in the illustration indicate the main pancreas duct (MPD), the biliary tree and the gallbladder. The main pancreatic duct is dilated (7 mm) and also is markedly curved like an S-shape in the pancreas head. A lesion consisting of multiple dilated branch pancreas ducts (BPD), illustrated as a cluster of gray areas, is seen in the pancreas head. C) Contrast-enhanced computed tomography findings in the portal venous phase. A markedly curved main pancreas duct and multiple dilated branch pancreas ducts (indicated by arrows) are seen in the pancreas head. No enhanced nodules are seen in either the main pancreas duct or dilated branch pancreas ducts.