Abstract

Context CA 19-9 is widely used as tumor marker of pancreatic cancer. Extra-pancreatic tumors with increased serum levels of CA 19-9 are uncommon but should be taken into consideration in some cases. Case report We present an asymptomatic case of highly elevated serum CA 19-9 related to lung adenocarcinoma but not to pancreatic tumors. The serum CA 19-9 level returned to nearly normal after chemo-radiotherapy for lung cancer. Conclusion In addition to pancreatic cancer, highly elevated serum levels of CA 19-9 may be present in other extra-pancreatic conditions such as lung cancer in this case. A physician should not limit tumor survey in biliopancreatic fields in a patient with highly elevated serum CA 19-9 and clinical suspicion of malignancy.