This paper reports on a patient who was treated by percutaneous aspiration, instillation of a sclerosant (polidocanol) and cystogastric drainage for a post-acute pancreatic pseudocyst. Five weeks after admission to hospital for the first episode of an acute necrotizing pancreatitis, the 60-year-old man underwent a percutaneous, ultrasound-guided puncture and aspiration of a voluminous pancreatic pseudocyst. Ten days later, recurrent fluid collection led to a second puncture, combined with the injection of polidocanol (15 ml; 1%) into the cyst cavity. Since this treatment failed, a percutaneous cystogastric drain ("double--pigtail") was inserted five days later. After developing acute abdominal pain and incipient sepsis, the patient was sent for surgical intervention twelve days after the second treatment with percutaneous aspiration and injection of polidocanol. During the operation an infected pancreatic pseudocyst with extensive contaminated necrosis of the pancreas and duodenal perforation was found. Necrectomy was performed, followed by continuous lavage of the omental bursa. Intensive care therapy was necessary for one week. Duodenal leakage persisted for nearly three weeks, the stopped spontaneously. The patient was discharged in quite a good state of health after 33 days of postoperative treatment. Although spontaneous development of infected pancreatic pseudocysts and pancreatic abscesses in necrotizing pancreatitis is known, a possible involvement of the drainage procedures, especially in combination with the injection of a sclerosant must be considered.