Intraductal papillary mucinous adenoma of the pancreas differentiated from pancreatic cancer with difficulty due to high FDG accumulation

Abstract

An abdominal CT indicated a cystic lesion on the pancreatic tail in an 83-year-old woman in November 2010. In May 2012, she was introduced to our department because the cystic lesion had enlarged. Abdominal CT at that time showed that the cyst wall of the pancreatic tail had thickened with a solid nodule appearing in the cyst. Abdominal MRI and MRCP also detected the cyst in the pancreatic tail, although no communication between the cystic lesion and main pancreatic duct could be found. Endoscopic ultrasound (EUS) indicated that a part of the nodule invaded the pancreatic parenchyma. Furthermore, FDG-PET/CT revealed a high fluorine-18-deoxyglucose (FDG) accumulation in the pancreatic tail. The cystic lesion with a solid mass was diagnosed as intraductal papillary mucinous neoplasm-derived invasive pancreatic cancer, and we conducted distal pancreatectomy. Based on histopathological findings of the resected pancreas, the tumor was diagnosed to be intraductal papillary mucinous adenoma without any malignancy. When the cyst enlarged rapidly and the solid component appeared, it was necessary to consider the possibility of pancreatitis, even if the tumor exhibited a high up-take of FDG.