A case of intrahepatic gallstone formation around nylon suture for hepatectomy

A 69-year-old female underwent left lobectomy for hepatolithiasis in February 1994. She was admitted to the Kurume University Hospital in December 1997 because computed tomography (CT) showed calcification in the porta hepatis. Ultrasonography (US) revealed a hyperechoic area with an acoustic shadow in the right hepatic duct. Dilated intrahepatic bile ducts and a mural lucent area in the right hepatic duct were noted on endoscopic retrograde cholangiography (ERC). Although the above findings suggested a diagnosis of recurrent hepatolithiasis, percutaneous transhepatic biliary drainage (PTBD) for biopsy was performed in order to rule out cancer. Biopsy showed no evidence of malignancy. Under a cholangioscope, a tip of a nylon suture was found to be protruding into the bile duct. Although a gallstone had already slipped off, the surface of the nylon suture was covered with biliary sludge. The protruding tip of the nylon suture was considered to be the nucleus of the stone. The tip was removed under cholangioscopy. Postoperative CT confirmed the absence of calcification in the porta hepatis. There has been no recurrence of hepatolithiasis after surgery. Although the formation of gallstones around the core of nylon sutures is very rare, absorbable sutures should be used during surgery of the bile duct because nonabsorbable sutures can become the nucleus of gallstones.