Mucinous Cystic Neoplasm of the Pancreas Presenting with Acute Pancreatitis: Report of a Case

Acute pancreatitis is only rarely the first presentation of a cystic neoplasm of the pancreas, especially mucinous cystic neoplasm. However, a 60-year-old woman was admitted to our hospital with a history of recurrent pancreatitis and a pseudocyst diagnosed six months ago. Abdominal computed tomography (CT) revealed an encapsulated cystic leson 11 cm x 9.7 cm in size in the pancreatic tail. A communication between the cystic lesion and the main pancreatic duct (MPD) was suspected by CT. Endoscopic ultrasonography demonstrated no mural nodule or septum in the cystic lesion and still suspected the MPD connected with this cystic lesion through an infundibuliform structure. Pancreatic pseudocyst was favored due to the history of pancreatitis, no mural nodule, no septum and a communication with the MPD. Surgical intervention for the pseudocyst was suggested for symptomatic pseudocyst without regression in the past six months. An endoscopic retrograde pancreatography before the operation showed a tortous dilated MPD with interruption and no contrast medium leakage into the cystic lesion. During the operation, no inflammation adhesion was found between the huge cystic lesion and the surrounding tissue. Intraoperative aspiration of the cystic fluid revealed mucin and a mucinous cystic neoplasm was diagnosed. The final pathologic diagnosis was benign mucinous cystic neoplasm (mucinous cystadenoma).Pre-operative differential diagnosis between inflammatory and neoplastic cysts is difficult, especially when the patient's first presentation is an episode of acute pancreatitis. A neoplastic cyst should be considered when acute pancreatitis attacks occur in non-alcoholic women, who do not have gallstone disease.