Background: The double duct sign, a simultaneous stenosis of the common bile duct and the pancreatic duct by endoscopic retrograde cholangiopancreatography (ERCP), has been reported to predict the presence of pancreatic cancer with a high degree of certainty.
Methods: To test the specificity of the double duct sign for pancreatic cancer in patients with malignant and benign pancreatic lesions, we have reviewed all ERCP films obtained during a 24-month period (n = 1209) and corresponding clinical follow-up data obtained during a period of 4 years.
Results: Forty-three patients were identified as having a double duct stenosis on ERCP, 15% of whom did not have pancreatic carcinoma. In 4 patients chronic pancreatitis was confirmed by serial histologic sections of the surgical specimen. Data on the lengths of the stenotic segment in either the pancreatic duct or the bile duct did not contribute to a better discrimination between benign and malignant disease.
Conclusion: The specificity of the double duct sign in predicting the presence of pancreatic cancer appears to be lower than previously reported. Better discrimination between malignant and benign disease of the pancreas will be difficult to achieve with existing imaging techniques.