LAUSR

A 72-year-old man with pancreatic cancer presented with abdominal pain and hematemesis. One-year prior admission, the patient underwent implantation of an uncovered self-expendable metallic stent (SEMS). The patient’s tumor continued to grow; therefore, 2 months before presentation, a novel double-pit-type plastic stent (PS) (D-pit; Through & Pass D-pit, GADELIUS Medical, Japan) was placed into the left hepatic duct via the stent-in-stent method (Figs 1a and 2a). At admission, laboratory tests revealed anemia, leukocytosis, and elevated alkaline phosphatase, γ-glutamyl transferase, and bilirubin levels. Abdominal computed tomography (CT) revealed a high-density area in the bile duct (Fig. 1b). We suspected hemobilia secondary to the pancreatic tumor. Emergency endoscopic retrograde cholangiopancreatography was performed, and blood flow from the major papilla was detected. Hence, endoscopic nasobiliary drainagewas performed (Fig. 1c). A fully covered SEMS was inserted into the uncovered SEMS; however, the patient’s symptoms persisted. On the third day after admission, contrast-enhanced CT revealed a pseudoaneurysm of the left hepatic artery, which coincided with the tip of the inserted D-pit (Figs 1d and 2b). The hemobilia was attributed to the rupture of the pseudoaneurysm. Hepatic angiography and coil embolization were performed, and patient’s symptoms and laboratory findings improved. Pseudoaneurysms caused by PSs are rare, and there have been few reports on this entity. In this case, the location of the pseudoaneurysm matched that of the tip of the D-pit, strongly indicating that the physical pressure of the tip of the stent might have induced the formation of hepatic artery pseudoaneurysm. Both ends of the D-pit have a unique loop shape with a diameter of 23 mm and 225 degrees. Its unique loop shape allows it to hook the intrahepatic bile duct to prevent stent deviation and to reduce the pressure by the stent on the liver. However, in this case, it might have caused complication. To the best of our knowledge, this is the first report of a pseudoaneurysm owing to a D-pit. We should consider the risk of a D-pit causing a pseudoaneurysm even if the device is correctly placed.