CHRONIC ASYMPTOMATIC PSEUDOCYST WITH SLUDGE AGGREGATES MASQUERADING AS MUCINOUS CYSTIC NEOPLASM OF THE PANCREAS

Pseudocyst of the pancreas is sometimes difficult to distinguish from mucinous cystic neoplasm of the pancreas. A 37-year-old asymptomatic J apanese man was diagnosed with hypertension. He had a 20-years history of habitual drinking of alcohol, but no history of pancreatitis or ab dominal trauma. During examinations to ascertain the cause of hyperten sion, ultrasonography and computed tomography incidentally demonstrate d a huge cyst in the head of the pancreas. Laboratory data were within normal limits, including serum levels of amylase, carcinoembryonic an tigen, and carbohydrate antigen 19-9. Imaging studies showed a huge un ilocular cyst, measuring 7 cm, in the head-to-body of the pancreas, an d two small unilocular cysts, measuring 1.4 and 1.5 cm, in the tail an d head of the pancreas, respectively. A mural nodule was suspected in the largest cyst. Endoscopic retrograde cholangiopancreatography demon strated communication of the main pancreatic duct with the two small c ysts in the head and tail of the pancreas but not with the huge cyst. There were no ductal changes suggesting chronic pancreatitis. Laparoto my was performed under the tentative diagnosis of potentially malignan t mucinous cystic neoplasms of the pancreas. However, inflammatory adh esion was dense around the pancreas and the mural nodule suspected pre operatively was found to be sludge aggregates in a pseudocyst. The dia gnosis of an intraoperative frozen section of the cyst wall was pseudo cyst of the pancreas. Cystojejunostomy was performed. We report this c ase because the preoperative diagnosis was mucinous cystic neoplasm of the pancreas, but the diagnosis changed with careful intraoperative e xaminations, to pseudocyst of the pancreas. We discuss the differentia l diagnosis of the two conditions.