Small-Bowel Impaction Caused by Mechanical Interlocking Between Duodenal Metal and Biliary Plastic Stents.

Duodenal self-expandable metal stents (SEMS) are widely used to treat malignant gastric outlet obstruction (GOO). However, stent migration is a well-known complication. We report a rare case of small-bowel impaction caused by the migration of a duodenal SEMS with a biliary plastic stent (PS). A 78-year-old woman with pancreatic head cancer underwent biliary PS and duodenal SEMS placement for obstructive jaundice and GOO. At 4 months after initiating neoadjuvant chemotherapy, computed tomography revealed tumor shrinkage and improvement in duodenal stenosis; however, the SEMS and PS had migrated to the ileum. Double-balloon enteroscopy was attempted; however, stent removal was unsuccessful because of mechanical interlocking and impaction. Therefore, a partial ileal resection was performed. Histopathological examination revealed transmural infiltration of inflammatory cells and abscess formation. If a duodenal SEMS migrates with a biliary PS, mechanical interlocking may occur, resulting in small-bowel impaction. Clinicians should be aware of this rare complication and should consider careful follow-up and timely intervention if stent migration is detected. Trial Registration: N/A.