Abstract
Obstructive jaundice caused by metastases to the porta hepatis is often observed in patients with various advanced cancers; however, metastasis of lung cancer to the common bile duct with subsequent development of jaundice is rare. A 75-year-old female with lung adenocarcinoma harboring epidermal growth factor receptor (EGFR) mutation (15-bp in-frame deletion in exon 19 and T790M in exon 20) developed obstructive jaundice during therapy. Obstruction of the common bile duct caused by an intraductal tumor was identified by computed tomography, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasonography. Although primary cholangiocarcinoma was highly suspected according to the imaging findings, immunohistochemical evaluation of the intraductal tumor demonstrated thyroid transcription factor-1 positive adenocarcinoma. Furthermore, peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp analysis showed that the tumor contained the same EGFR mutation as that in the primary lung cancer. Thus, we confirmed intraductal metastasis from a lung adenocarcinoma. To our knowledge, this is the second report of obstructive jaundice caused by intraductal metastasis of lung cancer.