Hemobilia is caused by iatrogenic factors, trauma, and neoplasms. In recent years, hemobilia has mainly been caused by iatrogenic factors, including IVR, which can be explained by the popularization of hepatopancreatobiliary intervention [6]. Hemobilia is a rare symptom, even more rare, except for traumatic and iatrogenic causes. Therefore, the diagnosis of hemobilia is generally difficult. Because the nothing of unique findings of hemobilia, not only various diagnostic imaging techniques, but also a detailed clinical history is important for its diagnosis [7]. Additionally, the diagnosis of hemobilia was difficult in this case, as a previous doctor diagnosed the cause of hemorrhage as a hemorrhagic pancreatic pseudocyst. Records of the operation performed for CBD 62 years prior were not available. Based on the CT findings, IVR images, and considering the standard operative method for CBD in the 1950s, we determined that the patient underwent IDS for CBD instead of division surgery which is currently used as a standard operation.

The purposes of treatment for hemobilia are hemostasis and maintaining bile flow. The latter is especially important because of the development of cholangitis or pancreatitis due to blood clots in the biliary tract [8]. Various treatments for hemobilia, including follow-up observation, endoscopic approaches, and surgery, depend on the cause or degree of hemorrhage. IVR, as a diagnostic and treatment modality, is effective for patients for whom hemodynamics are unstable due to active hemorrhage [7]. In our case, IVR was chosen because the patient was in hemorrhagic shock. Generally, the blood flow of the extrahepatic bile duct is supplied from the left and right hepatic arteries, cystic artery, proper hepatic artery, and posterior superior pancreaticoduodenal artery. These arteries form the complex PBP [9]. Additionally, considering that extravasation was not observed in the supplying arteries to the pancreatic head from the pancreaticoduodenal arcade, the patient was diagnosed not with hemorrhage from pseudopancreatic cysts but with hemorrhage in the remnant dilated bile duct lumen. Furthermore, in our case, extravasation occurred from a pseudoaneurysm developed in the branch of the proper hepatic artery. Although selective TAE was successfully performed and hemostasis was obtained, there was concern about the possibility of rehemorrhage from the PBP. Therefore, extrahepatic bile duct resection with bilioenteric reanastomosis was performed to prevent rehemorrhage.

For a long time, CBD had been considered an indication for surgery because it was known to cause cholangitis, obstructive jaundice, hepatitis, and spontaneous rupture, and many untreated patients died after follow-up [10]. However, division surgery (i.e., resection and reconstruction of the extrahepatic bile duct to prevent oncogenesis) was not generally performed. Therefore, the standard operation for CBD was simple IDS (i.e., anastomosis between the gallbladder and nearby digestive tract or between the extrahepatic bile duct and digestive tract). However, gallbladder–neighbor digestive tract anastomosis was problematic, as bile excretion was not satisfactory. On the other hand, extrahepatic bile duct resection was rarely performed since the procedure is complicated and thus leads to high mortality. Therefore, IDS in which the dilated bile duct and digestive tract were directly anastomosed (e.g., choledochocystoduodenostomy or choledochocystojejunostomy in a Roux-en-Y fashion) was usually chosen as the standard operation to prevent reflux cholangitis and secure an improvement of jaundice [10]. Later, the risk of oncogenesis after IDS was reported [11]. Because IDS has an approximately fourfold increased risk of oncogenesis compared with extrahepatic bile duct resection and gallbladder resection with bile tract reconstruction, IDS is not currently the standard operation [12, 13]. In fact, approximately 21.6% of adult CBD patients with biliary dilation were revealed to develop cholangiocarcinoma during the natural course [14]. According to the Cancer Registry and Statistics, Cancer Information Service, National Cancer Center, Japan (Vital Statistics of Japan), the incidence rate of cholangiocarcinoma in Japanese patients is 0.018% [15]. Therefore, CBD patients with biliary dilation have an approximately 1200 times higher risk of cholangiocarcinoma. In our case, CIS was found incidentally in a very limited location during the pathological examination. Furthermore, regardless of the location of the CIS, abnormal angiogenesis and microscopic hemorrhage were extensively observed under the mucosal epithelium of the extracted bile duct. Based on these findings, CIS and bleeding are unrelated, and the formation and collapse of pseudoaneurysm due to chronic inflammation over many years was considered the cause of biliary hemorrhage.

In the case of cholelithiasis, it is generally known that chronic inflammation causes erosion or ulceration in the gallbladder mucosa, followed by rupture of the submucosal artery, and pseudoaneurysm is formed due to repeated hemorrhage and thrombolization [16]. In the case of CBD, bile and refluxed pancreatic juice are mixed in the bile duct due to the pancreaticobiliary maljunction, activating pancreatic juice with bacterial infection, and continuous inflammation is present in the bile duct mucosa [17]. Therefore, the cause of hemobilia was interpreted to be pseudoaneurysm that developed and ruptured due to long-term and severe chronic inflammation of the bile duct mucosa [18]. In our case, to pathologically identify the ruptured pseudoaneurysm, we performed EVG staining which highlights elastic fibers of blood vessels. However, we could not find any responsible lesions probably because the bile duct was so inflamed that we resected the specimen piece by piece. Therefore, we diagnosed that hemobilia was due to rupture of pseudoaneurysm based on IVR findings and clinical features. IVR showed a clear pseudoaneurysm, and the clinical course showed that the patient had been in shock status due to massive gastrointestinal bleeding and quickly recovered after embolization of the pseudoaneurysm. Additionally, it was interpreted that the bile duct mucosa was exposed to severe chronic inflammation for a long time because an activated pancreatic juice, intestinal juice or bacteria flowed into the remnant dilated bile duct through the anastomosis of IDS.

Generally, massive hemorrhage is rare in hemobilia because hemorrhage is suppressed with high intraluminal pressure, especially in the case of a thickened bile duct due to chronic inflammation [19]. Although a thickened bile duct, which is a characteristic of CBD, was observed in our case, the most notable point is that the intraductal pressure could not increase to suppress bleeding because the blood flowed out into the jejunum through the anastomosis [20]. Thus, the patient was believed to have easily developed hemorrhagic shock associated with massive hemobilia.

A search of PubMed using the keywords "haemobilia", "hemobilia", "choledochal cyst", and "congenital biliary dilation" from 1948 to 2020 revealed only two cases of hemobilia in CBD. One report reviewed hemobilia from a ruptured pseudoaneurysm due to inflammation in a 21-month-old girl. Hemostasis was obtained with TAE, and division surgery was performed [21]. The other report reviewed hemobilia from benign biliary papillomatosis in a 57-year-old woman. Division surgery was performed, and the patient was followed up uneventfully for 4 years after surgery [22]. Our case which exhibited hemobilia in the CBD patient had been performed IDS is the first report in the world literature.