An 86-year-old woman with obstructive jaundice presented with high serum CA19-9 concentrations and stenosis of the common bile duct with intrahepatic bile duct dilation. Despite the lack of evidence of pathological malignant findings, we diagnosed the patient with distal cholangiocarcinoma based on the clinical findings. We placed a covered-type self-expandable metallic stent (SEMS) (10×70 mm) inside the common bile duct, and her symptoms improved. She underwent chemotherapy with S-1 for 10 months, but her CA19-9 concentration gradually increased. Computed tomography showed intrahepatic bile duct dilation and the resolution of pneumobilia, suggesting dysfunction of the SEMS. Although we performed endoscopic retrograde cholangiography, the SEMS had disappeared from her body with no symptoms. We speculated that the SEMS migrated from the common bile duct and was excreted asymptomatically. The covered-type SEMS is recommended for the drainage of malignant biliary obstruction for the prevention of tumor ingrowth; however, it migrates more frequently than the uncovered-type SEMS and causes clinical problems. We, thus, report a rare case of asymptomatic migration and disappearance of a SEMS.
