Serous cystadenoma of the pancreas associated with pancreas divisum

Pancreas divisum is an embryologic anomaly of the pancreas that is characterized by a lack of fusion of the dorsal and ventral pancreatic ducts. It is rarely associated with pancreatic neoplasms. We report herein a rare association of pancreas divisum and serous cystadenoma of the pancreas. A 46-year-old Japanese woman presented with epigastralgia. Ultrasonography, computed tomography (CT) and magnetic resonance cholangiopancreatography revealed a multilocular cystic mass, measuring 7 cm in diameter, with a central stellate scar, in the body and tail of the pancreas. Angiography demonstrated a relatively hypervascular mass, suppressing the splenic vein. No arterial encasement was evident. Endoscopic retrograde pancreatography through the major papilla demonstrated only the duct of Wirsung; cannulation into the minor papilla was unsuccessful. In addition, CT showed a mildly dilated main pancreatic duct draining into the minor papilla. Distal pancreatectomy and splenectomy were performed, with the tentative diagnosis being serous cystic neoplasm of the pancreas, possibly malignant, and pancreas divisum. The cut surface of the resected specimen had a honeycomb-like appearance and the specimen consisted of multiple cysts of various sizes. Histopathological examination showed multiple cysts lined by a single layer of flat or cuboidal epithelial cells with glycogen in the cytoplasm. There was no evidence of malignancy. The histopathological diagnosis was serous cystadenoma of the pancreas. To the best of our knowledge, only three cases of serous cystadenoma of the pancreas associated with pancreas divisum have been reported. We report the fourth case of such an association, and briefly review the literature.