False-Positive Cytology in Diagnostic Laparoscopy due to Ectopic Pancreas

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.