False elevation of CA 19-9 levels in a patient with a history of pancreatic cancer.

CA 19-9 is the most sensitive and specific marker currently used in the diagnosis of pancreatic cancer. Its interpretation, however, can be limited in the presence of certain nonmalignant diseases that have been correlated with elevated serum levels of CA 19-9. We report an unusual case of falsely elevated CA 19-9 levels in a patient with a history of resected pancreatic cancer. This patient presented 4 yr after resection with painless jaundice and markedly elevated CA 19-9 levels (2327 U/ml). Although it was initially suspected that the patient had recurrent cancer, further evaluation proved that her jaundice and increased CA 19-9 value were due to a benign stricture that led to cholestatic jaundice and concomitant cholangitis. No previous cases of falsely elevated CA 19-9 levels have been reported in the context of a known history of pancreatic cancer. Physicians should be aware of the perturbations that extrahepatic cholestasis and certain inflammatory diseases of the pancreas and hepatobiliary system may impose on CA 19-9 levels. Furthermore, this case demonstrates that even markedly elevated CA 19-9 levels in patients being assessed for recurrence of pancreatic cancer need to be carefully interpreted in the context of other clinical findings.