Background: Report on a case of incorrect diagnosis after laparoscopy and peritoneal fluid sampling. Methods: Case description and literature review. Results: Diagnostic laparoscopy is a frequently used tool. In a patient with chronic abdominal pain, a diagnostic laparoscopy was performed, and a peritoneal fluid sample was taken. Cytology of the aspirated peritoneal fluid revealed an adenocarcinoma. At laparotomy, ectopic pancreas was found as the source of the false-positive cytology, Conclusion: In the diagnosis of adenocarcinomas from peritoneal fluid aspirates without an obvious clinical location (tumor), ectopic pancreatic tissue should be considered in the differential diagnosis. Copyright (C) 1999 S. Karger AG, Basel.