Removal of an embedded "covered" biliary stent by the "stent-in-stent" technique

A 46-year-old man was admitted with obstructive jaundice and cross-sectional imaging with computed tomography suggested distal biliary obstruction.A distal common bile duct stricture was found at endoscopic retrograde cholangiopancreatography(ERCP)and cytology was benign.A 6 cm fully covered self-expanding metal stent(SEMS)was inserted across the stricture to optimize biliary drainage.However,the SEMS could not be removed at repeat ERCP a few months later.A further fully covered SEMS was inserted within the existing stent to enable extraction and both stents were retrieved successfully a few weeks later.Fully covered biliary(SEMS)are used to treat benign biliary strictures.This is the first reported case of inability to remove a fully-covered biliary SEMS.Possible reasons for this include tissue hyperplasia and consequent overgrowth into the stent proximally,or chemical or mechanical damage to the polymer covering of the stent.Application of the stent-in-stent technique allowed successful retrieval of the initial stent.