A 60-year-old patient with a history of chronic pancreatitis and insulin-dependent diabetes was admitted to our hospital with a deeply excavated duodenal ulcer showing no signs of regression under 4-week parenteral nutrition and proton pump inhibitor therapy. Radiologic and endoscopic diagnostics could demonstrate a primary tumor of the pancreatic head penetrating into the duodenal lumen. After surgical treatment by pylorus-preserving pancreatoduodenectomy an abscessing intraductal papillary-mucinous neoplasm of the pancreas was established morphologically.