Common Bile Duct Stone Formed Around an Ingested Fish Bone

An 86-year-old man presented with epigastric pain. He had previously undergone distal gastrectomy with Roux-en-Y reconstruction. Computed tomography (CT) revealed a 32×17 mm common bile duct (CBD) stone with an internal 20 mm linear hyperdense component. Endoscopic removal was unsuccessful due to the size and impaction of the stone. Open choledochotomy retrieved multiple stones and a calcified fish bone, which was confirmed by infrared spectroscopy using the potassium bromide (KBr) wafer method. Although fish bone ingestion is relatively common, this case highlights that such foreign bodies can occasionally serve as a nidus for CBD stone formation, leading to unexpected and clinically significant pathologies. When CT demonstrates a linear high-attenuation intraductal structure, clinicians should suspect a bone fragment and follow a stepwise approach, considering early surgical intervention when endoscopic extraction is unsuccessful or likely to be challenging.