Macrocystic type of serous cystadenoma with a communication between the cyst and pancreatic duct.

A 42-year-old woman with a cystic lesion in the head of the pancreas was evaluated by using abdominal ultrasonography, a computed tomographic scan, magnetic resonance imaging and endoscopic retrograde pancreatography. Multiple cystic lesions, 5 cm in diameter, which had papillary protrusion inside the cyst in the head of the pancreas and had the communication between the cysts and pancreatic duct, were determined. Pylorus-preserving pancreaticoduodenectomy was performed under the diagnosis of mucinous cystic neoplasm of the pancreas. Although the cut surface of the tumor showed a macrocystic tumor of 3 cm in diameter, part of the cyst wall was cavernous. A histopathological examination showed single-layered cuboidal cells, which lead to the diagnosis as being serous cystadenoma of the pancreas. Serous cystadenoma is a rare, almost benign pancreatic tumor. The macrocystic subtype of serous cystadenoma is even more rare. We describe a patient who had this macrocystic subtype of serous cystadenoma with a communication between the cyst and pancreatic duct. This case illustrates the difficulty in the diagnosis of cystic lesions in the pancreas, and might support the single category of cystic lesions of the pancreas.