A Case of Pancreatic Macrocystic Serous Neoplasm Difficult to Differentiate from Mucinous Cystic Neoplasm

Abstract

A 71–year–old woman admitted in May 2005 for a growing pancreatic cyst seen in follow–up was found in abdominal ultrasonography, computed tomography, and magnetic resonance imaging to have a multilocular 68×62×52 mm cystic lesion in the pancreatic tail. The lesion contained cysts a maximum of 3 cm in diameter and blood flow within the diaphragm. Imaging results suggested a mucinous cystic neoplasm (MCN), necessitating resection of the pancreatic tail with splenectomy, followed by two–group lymph node dissection. Histopathological examination of the resected specimen showed cyst contents clear, colorless serous. Flat and cubic tumor cells in a single layer covering the cyst wall were positive in periodic acid–Schiff (PAS) staining. No findings indicated malignancy. The definitive diagnosis was macrocystic (variant) serous cystic neoplasm (SCN). A macrocystic subtype is rarely reported in SCN and should be carefully differentiated from mucinous cystic neoplasm (MCN) and intraductal papillary mucinous neoplasm (IPMN).