[A Case of Unilocular Serous Cystic Neoplasm Mimicking Mucinous Cystic Neoplasm].

A 40's woman had a cystic lesion in the tail of the pancreas that had grown over a 1.5-year period. Endoscopic ultrasound revealed a partition structure and "cyst-in-cyst" like lesion, and a diagnosis of mucinous cystic neoplasm was made. The patient underwent distal pancreatectomy with splenectomy. Following histological examination, our final diagnosis was revised to unilocular serous cystic neoplasm since the increase in cysts was due to hemorrhage and the partition structure was in fact granulation tissue. We here discuss this rare case with reference to previous published reports.