BACKGROUND AND METHODS: The authors describe the rising of four postoperative pancreatic pseudocysts in a series of 20 patients treated for periampullary tumours by pancreaticoduodenectomy (PDT), with the closure of pancreatic stump, between 1989-1996. The operation was always performed by the pylorus-preserving technique according to Traverso-Longmire. RESULTS: In four patients (20%) 3, 4, 4, and 8 months after PDT with closure of the pancreatic stump, the authors observed the development of pseudocysts (PPC) in the pancreatic remnant. All these patients previously had a pancreatic fistula. Three symptomatic patients underwent surgical drainage of the pseudocyst in a jejunal loop (2) or in the stomach (1); in the asymptomatic patient, the clinical feature and the size of the cyst allowed for conservative treatment. In 2 cases PPC was the consequence of a pancreatic fistula evolved in acute pancreatitis of the stump. The PPC drained by cystogastrostomy appeared 4 months after the closure of the pancreatic fistula: the pancreatic stump was completely substituted by a cyst presenting a communication with the pancreatic duct. CONCLUSIONS: The authors conclude that PPC is a rare complication of the pancreatic resection that results from acute or chronic pancreatitis; sometimes pathogenesis is due to a cyst resulting from the pancreatic duct occlusion by phlogistic tissue as a consequence of the surgical suture.