Unexplained biliary tract dilatation in lung cancer patients.

Three patients, two men and one woman, diagnosed as having adenocarcinoma of the lung were found to have changes in cholestatic biochemical values, and CT scan of the abdomen demonstrated dilation of the biliary tree. Upon further evaluation using ERCP marked dilation of the biliary tree was confirmed. There was no anatomic obstruction to bile flow, no neoplastic involvement of the liver or bile ducts and no evidence of any infiltrative process or disease to explain the dilation. A paraneoplastic syndrome is proposed as the etiology of the biliary tract abnormality. Along with other more common causes, this newly described paraneoplastic syndrome should be considered in the differential diagnosis of lung cancer in patients presenting with cholestasis and biliary tract dilation.