At times, the papilla of Vater can terminate at aberrant sites, including the stomach, pyloric canal, duodenal bulb, and the third or fourth portion of the duodenum. This is named as ectopic biliary drainage and it is a rather rare condition. Although, we do not know the exact frequency of ectopic biliary drainage, the frequency of the ectopic biliary drainage was found to be 2% in our series. In 2001, Bernard P et al. reported only 23 cases with this condition by then [9]. In the literature, there were some other small case series and when we analyzed all these cases, we noticed that they were mostly patients with double choledochus [9–12]. Lee and et al from Korea indicated 18 cases with this anomaly out of 16541 ERCP records [8]. The largest case series in the literature was published by Disibeyaz and et al from Turkey reported 53 patients (0.43%) with ectopic biliary drainage out of 12158 ERCP records [13]. In these big series of patients with this anomaly, there was no record of any case with ectopic drainage into the stomach. Lindler and et al. reviewed their 1000 intraoperative cholangiograms and reported that ectopic biliary drainage distal to the second part of the duodenum was present in 13.1% of the cases [14]. However, we believe that it is insufficient to evaluate only cholangiograms and, diagnostic potential of endoscopy visualizing the exact site or origin of biliary drainage into the duodenum or stomach seems to be superior to operative cholangiograms.
Etiology and classification
Though we do not know its etiology, it must be due to an abnormality during the embryonic developmental period. For up to 8 weeks of gestation, the extra-hepatic biliary tree develops through lengthening of the caudal part of the hepatic diverticulum. The hepatic duct (ductus hepaticus) develops from the cranial part (pars hepatica) of the hepatic diverticulum. The distal portions of the right and left hepatic ducts develop from the extrahepatic ducts and are clearly defined tubular structures by 12 weeks of gestation. The proximal portions of the main hilar ducts derive from the first intrahepatic ductal plates. In the first weeks of embryogenesis, if subdivision occurs very early, leaving the pars hepatica above the zone of growth that separates stomach from duodenum, then the pars hepatica will develop into a duct emptying into the region of the pylorus [7]. Very rarely, two choledochus with 2 different opening orifices into the duodenum can be seen [15]. However mostly, the choledochus which would open into the duodenum at its usual position becomes rudimentary and the other one with a fully developed channel drain into an ectopic opening in the stomach or duodenum.
Kanematsu et al. proposed the classification of the congenital anomalies associated with ectopic drainage of the biliary tract in the following 4 types [11]:
Type I: There is one septated draining duct, which enters the stomach.
Type II: Division of the common bile duct in 2 separate junctions, one of which enters the normal position of the papilla of Vater, whereas the second one enters the stomach.
Type III: Presence of 2 independent draining ducts, one of which enters the normal position of the papilla of Vater, whereas the second one enters the stomach.
Type IV: Presence of 2 independent draining ducts, one of which enters the normal position of the papilla of Vater, whereas the second one enters the stomach and share one or more intercommunications.
The most common location of the ectopic biliary drainage into the stomach is the corpus of the stomach, followed by the antrum and cardia. One of our cases had ectopic biliary and pancreatic channel drainage into gastric antrum. Ectopic biliary drainage into the third and fourth part of the duodenum was not present in our series. These conditions have been reported to associate with pancreatic divisum and long common channel anomaly [16, 17]. There has been no ulcer formation in ectopic biliary drainage anomaly in the distal duodenum. In our case with postbulbar ectopic drainage condition, he had no complaints of ulcer disease. This may be due to the resistance of postbulbar duodenal mucosa to bile and duodenal peristaltism helps this by decreasing bile contact with duodenal mucosa.
Demographics and clinics
In the literature, more than 80% of the cases with ectopic biliary drainage into the bulbar duodenum were reported to be the male gender. In our series, 90% of the patients had male gender. This might bring to mind the etiologic relation with Y chromosome-induced embryonic abnormality. However, this condition can also be seen in female patients. Proximal ectopic biliary drainage seemed to be common in middle-aged patients and distal ectopic opening was commonly encountered in pediatric population. Our patients were over 50 years of age when they were diagnosed with ectopic biliary drainage. These cases became symptomatic at the 4th or 5th decades of life with signs and symptoms of cholangitis and upper gastrointestinal bleeding. Due to absence of a sphincteric structure, chronic regurgitation of intestinal contents into the biliary tree leads to recurrent cholangitis attacks, biliary stone formation and distal biliary stricture [6–8]. Bile reflux into the duodenal bulbus and the stomach causes ulcer formation and its associated complications [6–8]. In the literature, 2 cases with ectopic biliary drainage were diagnosed with gastric cancer and precancerous changes around the ectopic biliary opening led to theories indicating possible relationship with gastric carcinogenesis. In summary, 80% of the patients had ulcer and ulcer-related complications.
Except for one case who developed cholangitis one week before his admission to our clinic and treated with medical methods, all had complaints due to biliary disease. The main indication for ERCP procedures undertaken in all cases was the presence of biliary symptoms and laboratory abnormalities. In our series, there was no case with incidental diagnosis of ectopic biliary drainage.
Diagnosis
The upper endoscopy and ERCP provide us with necessary information about this condition with detection of ectopic orifice and cholangiographic appearance. When the papilla vateri is not located at its original place in the second part of duodenum and moreover if there is associated ulcer formation, we have to think of ectopic biliary drainage anomaly. It is difficult to conduct a duodenoscopic examination in most of the patients with ectopic biliary drainage abnormality due to ulcer-related pyloric and duodenal deformity. In such cases, forward viewing gastroscopes can reveal the bulbus easily. Ectopic orifice, usually stained with bile, is a slit-like opening sized 2-3 mm. If there is no bile on it, an aspiration maneuver can reveal bile drainage. There is no classic papillary appearance in these cases. However, Kubota et al. indicated papillary-like protuberance in the duodenum bulbus in 2 cases [18]. On ERCP examination, distal choledochus has a hook-like appearance and is larger and shorter than normal choledochus. In some cases, there may be a short stricture at distal choledochus. Mostly these cases had dilated left intrahepatic biliary tree and occasionally, there are bile duct stones.
Less invasive or even non-invasive methods can be used for the diagnosis of this condition. Absence of the sphincteric muscle leads to pneumobilia in these cases. Pneumobilia can also be seen in the presence of choledochoduodenal fistula and choledochoduodenostomy. Thus, it is not specific for cases with ectopic biliary drainage problem. Some authors also propose that spontaneous passage of barium into the biliary tree support the diagnosis of ectopic biliary drainage problem. However, a similar finding can also be seen in cases with choledochoduodenostomy.
In the literature, we could not find any data about additional contribution of abdominal ultrasonography to the diagnosis of ectopic biliary drainage. An abdominal ultrasound examination showed dilated stomach in one of our cases admitted for obstructive jaundice. In this case, choledochus was 2.5 cm in maximal diameter and contained similarly large-size stones within its lumen. Though the choledochus was dilated but not tortuosed in appearance, we thought it to be shorter than its normal size. Gastric dilatation was attributed to gastric outlet obstruction due to bulbar ulcer. Thus, abdominal ultrasonography helped us to make an unequivocal diagnosis of ectopic biliary drainage. In the literature, there are case reports favoring the utility of endoscopic ultrasound examination and MR cholangio-pancreatography in the diagnosis of ectopic biliary drainage problem [10, 19–21]. In a case series of 8 patients with ectopic biliary drainage anomaly, computerized tomography could not reveal any specific finding [21].
Treatment
In routine clinical practice, the treatment of ectopic biliary drainage is towards biliary symptomatology and associated peptic ulcer complications [8, 13]. Gastric outlet obstruction can be handled with endoscopic balloon dilatations and/or surgical bypass methods. If there is ongoing cholangitis, physicians should treat cholangitis and also take some precautions to protect the patient against recurrent cholangitis attacks. The first-line treatment modality should be endoscopy in these patients as surgical treatments carry appreciable risks for them due to different anatomical composition. In patients with ectopic drainage problem, the entry site for choledochus to duodenum is a slit-like opening without a sphincteric structure and there is no intramural part of choledochus in these cases. Thus, sphincterotomy carries an appreciable difficulty and risk of retroduodenal perforation in such cases. Most authors advise extraction of bile stones after balloon dilating of ectopic opening site. If the case is elderly and stones cannot be extracted, then plastic biliary stents can be introduced after biliary drainage. Moreover, difficult stones in cases with gastric outlet obstruction can be managed best with surgery. It is generally agreed that these patients should undergo frequent endoscopic controls for early recognition and treatment of the above-mentioned complications. Some surgeons propose the resection of the common bile duct combined with hepaticojejunostomy to ameliorate the possible danger for the development of gastric adenocarcinoma. Other conservative approaches include the ligation of the ectopic draining duct (in cases of double opening) or the reinsertion of the ectopic bile duct in the duodenum [10, 11, 18]. However, informing the surgeon of the current anatomic problem in these cases would be of crucial importance to lower the risks in surgery. Based on our experience in our cases, we suggested a therapeutic flow-chart of ectopic biliary drainage (Figure 9).