Recurrent Migration of Fish Bone Foreign Bodies into the Intrahepatic Bile Duct After Pancreaticoduodenectomy Identified by DNA Metabarcoding: A Case Report with Pathophysiological Considerations.

Fish bone migration into the bile duct after pancreaticoduodenectomy (PD) is rare, and the mechanism of recurrent migration is unclear. We report a case in which multiple fish bones were repeatedly identified and removed from the intrahepatic bile duct during four endoscopic retrograde cholangiopancreatography procedures over more than six years after PD. The foreign bodies were definitively identified as fish bones using a component analysis and DNA metabarcoding. These findings suggest that recurrent migration may occur even in the absence of apparent anatomical abnormalities and it may be associated with postoperative intestinal dysmotility and altered intraluminal flow dynamics.