[Serous cystadenoma of the pancreas showing enlargement on images: a case report].

Serious Cystadenoma (SCA) of the Pancreas is seldom malignant and is usually monitored over time. Here we report a case of SCA an enlarged cyst that had to be excised because it was difficult to diagnose by intraductal papillary-mucinous neoplasm (IPMN). The patient was a 58-year-old woman with thecoma of the right ovary accompanied by Meigs syndrome, who had undergone abdominal total hysterectomy and bilateral oophorectomy. Abdominal computed tomography scan (CT) showed a multilocular cyst 2.4 cm in diameter in the head of the pancreas. Fourteen months later, a periodic CT showed that the multilocular cyst had enlarged from 2.4 to 3.5 cm in diameter. Branch duct intraductal papillary-mucinous neoplasm (IPMN) with a tendency to enlargement and with mural nodule was suspected. Pylorus-preserving pancreatoduodenectomy (PPPD) was performed, and pathological findings revealed that the cyst was lined with a single layer of simple cuboidal epithelium. Periodic acid-Shiff staining, with and without diastase digestion, showed abundant glycogen within epithelial cells, yielding a definitive diagnosis of SCA. The ascites were probably due to the Meigs syndrome pressing the cyst, and the size of the cyst appeared smaller than the real size.