Rapid shrinkage of a pancreatic serous cystadenoma with cystic degeneration: report of a case.

We report a rare case of pancreatic serous cystadenoma, which shrank remarkably from 6 to 1.5 cm in diameter, with cystic degeneration, over a period of only 3 weeks. A 29-year-old woman who presented with epigastric pain and jaundice underwent computed tomography, which showed a 6-cm monolocular cystic tumor in the pancreatic head. Endoscopic retrograde cholangiopancreatography showed stenosis and deviation of the inferior part of the extrahepatic bile duct. We performed surgery 3 weeks later for suspected mucinous cystadenoma or macroscopic serous cystadenoma of the pancreas. At laparotomy, the tumor in the pancreatic head was found to have shrunk remarkably. We excised the tumor completely by performing the Whipple procedure. Macroscopically, the mass was a 1.5-cm monolocular cyst. Microscopically, the cystic tumor was composed of a thick fibrous wall with granulation tissue and hemorrhage. Although epithelial cells were not found inside the cystic wall, numerous grossly invisible microcysts with glycogen-containing epithelial cells were seen at its periphery. Based on these findings, the tumor was diagnosed as a serous cystadenoma with cystic degeneration.