Congenital bronchobiliary fistula is a rare developmental abnormality with an abnormal fistula between the respiratory system and biliary tract. The aim of this report is to analyze and summarize the clinical features and experience of diagnosing and treating congenital bronchobiliary fistula (CBBF) occurring in the neonatal period.

The onset of symptoms was 3 d after birth in our patient with progressive cyanosis and respiratory distress, and a large amount of green fluid was noticed in her respiratory secretion. We performed computed tomography (CT), fiberoptic bronchoscopy, and cholangiography to make a diagnosis, as well as fistulography with a bronchoscope for the first time. These examinations provided us with valuable images to make a correct diagnosis. The fistula was dissected and removed with excellent results. Surgical removal of the fistula was successful, and the baby recovered well and was discharged. She has been followed for 4 mo without any signs of discomfort.

The main symptom of CBBF is bile-like sputum. CT, bronchoscopy, fistulography, and intraoperative cholangiography can provide important evidence for diagnosis. Surgical resection of the fistula is the first choice of treatment.

Congenital bronchobiliary fistula (CBBF) is a rare developmental abnormality with an abnormal fistula between the respiratory system (trachea or bronchus) and biliary tract. Patients with this anomaly may develop symptoms at any time from neonate age to adulthood, but most of them present with signs of apnea, bilious saliva, and choking, within just a few days after birth. Generally, the earlier the symptoms appear, the more serious the condition is. CBBF is often accompanied by biliary tract developmental anomalies, such as biliary atresia. Surgical resection of the fistula is the ultimate choice of treatment. Presently, this anomaly is believed to be caused by abnormal development of the foregut[1-3]. In this paper, we describe a patient with CBBF who showed the symptom of apnea at 3 d after birth, summarize the clinical data, and review the related papers on CBBF.

Congenital bronchobiliary fistula.

We initially performed laparoscopic biliary tract exploration and cholangiography to rule out biliary tract malformations. We found that the gallbladder was filled with green viscous bile, and the distal bile duct was patent. The abnormal fistula that bridged the intrahepatic bile duct and right bronchus was visible (Figure 3). Then, we performed posterolateral right thoracotomy at the sixth intercostal space. Green bile salt was deposited extensively beneath the visceral pleura. We dissected the mediastinal pleura and detected the fistula alongside the esophagus. The fistula formed down from the right bronchus to the right side of the hiatus, and it was about 4 mm in diameter and as soft as the esophagus. We punctured the lumen but produced nothing; then 10 mL of methylene blue was injected into the gallbladder, and the blue material was noticed subsequently at the puncture site and intratracheal tube (Figure 4). The fistula was confirmed accordingly. We separated the fistula and dissected it from the bronchus to the hiatus; both ends were securely ligated and sutured. Lastly, a thoracic drainage tube was placed.

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Figure 3 Intraoperative cholangiogram showing the connection between the biliary tract and right bronchus and patent distal bile duct; the white arrow indicates the biliary tract.

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Figure 4 Methylene blue was injected into the gallbladder, and it flowed out from the puncture site; the white arrow indicates the puncture site.

On the day 3 postoperatively, the child was successfully weaned from the ventilator. She was in good condition with satisfactory pulmonary expansion and feeding tolerance. We attempted to remove the thoracic drainage tube but failed; subsequently, the baby developed pneumothorax and subcutaneous emphysema, which were considered due to improper operation, so the tube was reinserted. On day 7 postoperatively, the child developed cholestasis with a total bilirubin level of 71.6 μmol/L and conjugated bilirubin level of 58.1 μmol/L. Ultrasonography showed mild obstruction of the extrahepatic bile duct and slight dilation of the common bile duct. Two possibilities were considered: first, the extrahepatic bile duct was not patent enough to drain all the bile produced by the liver sufficiently; and second, in-flammation and edema caused by the operation resulted in partial obstruction of the bile duct. Methylprednisolone was administered, and her bilirubin level decreased to normal range 3 d later. On day 10 postoperatively, growing chylous fluid was noticed in the drainage, so the oral feeding was withdrawn accordingly. Ten days later, the drainage gradually decreased, oral feeding was resumed without adverse reactions, and the drainage tube was removed. The baby recovered well and was discharged. She has been followed for 4 mo without any signs of discomfort.

A microscopic examination was performed separately for three parts of the removed fistula. Scattered mature and naive hyaline cartilage surrounded by clustered bronchial glands could be seen at the part near to the bronchus. Hyperplasia, angulation, aggregation, and columniation of the biliary glandular epithelial cells were found at the biliary end. The middle part was characterized by scattered, clustered glands, columniation of the glandular epithelia, squamous metaplasia, and cartilaginous tissue around the bronchial glands (Figure 5A-C).

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Figure 5 A microscopic examination performed separately for three parts of the removed fistula. A: The red arrow indicates the lumen that was partly covered by pseudo-ciliated columnar epithelium. The blue arrow indicates the cartilage rings that lay beneath the mucosa; B: The arrow indicates the clusters of bronchial glands at the end of the bronchus; C: The arrow indicates the glandular epithelia of the bile duct and interstitial cholestasis.

CBBF can manifest as a series of symptoms caused by an abnormal connection between the hepatic duct and trachea or bronchus. The onset time and severity of symptoms are related to the diameter of the fistula; therefore, the symptoms can appear at any age from newborn to adulthood. However, most of them occur in newborns and infants. The main clinical features of CBBF are recurrent coughing, bilious sputum, or bile-stained sputum in tracheal intubation. Patients generally develop progressive dyspnea, cyanosis, severe pneumonia, respiratory distress syndrome, and even apnea; shortly after birth, mechanical ventilation is often needed. Bile-stained expectoration is the most typical sign among the aforementioned symptoms. It has been often misdiagnosed as an esophagotracheal fistula, gastroesophageal reflux, aspiration pneumonia, or high intestinal obstruction[4,5].

The first findings on CBBF were reported in 1952 by Neuhauser et al[6]. Altogether, there were 43 additional cases reported in English and 1 in Chinese thereafter (Table 1), and CBBF was more common in women than in men. An abnormal fistula can be opened at different positions around the carina: right main bronchus (20/44, 45.4%), carina (19/44, 43.2%), and left main bronchus (5/44, 11.4%). Fistulas generally passed through the esophageal hiatus and entered into the abdominal cavity; all fistulas communicated with the intrahepatic bile duct (left hepatic duct), except one fistula that opened at the common bile duct[7].

The pathogenesis of this disease is not clear yet. Abnormal development of the bronchial bud, which fuses with the bile duct, was regarded as the cause of the anomaly. Other reports postulated that CBBF was the result of digestive tract duplication and the upper respiratory tract[1,6,8-10].

As in most reports, the proximal part of the fistula had the characteristics of the respiratory tract, consisting of cartilage, pulmonary epithelia, glands, and smooth muscle, whereas the distal part was similar to the gastrointestinal tract. In our case, by examining the proximal, middle, and distal parts of the fistula, we found scattered mature hyaline cartilage, relatively naive cartilage, and clusters of bronchial glands at the bronchus end; whereas, glandular epithelia of the bile duct and interstitial cholestasis were found at the distal part of the fistula. In the middle part, the lumen was partly covered by pseudo-ciliated columnar epithelia. Cartilage rings lay beneath the mucosa. Co-existing single-layer columnar epithelium could also be seen in the same field. These histological findings could further verify the pathogenesis of CBBF.

CBBF was often complicated by biliary atresia, diaphragmatic hernia, esophagus atresia, and tracheoesophageal fistula, and the incidence of biliary malformation in this group was about 30%[11-15]. As long as this possibility was considered, the diagnosis of CBBF was not difficult. Magnetic resonance imaging, 3D-CT reconstruction, bronchoscopy, and ultrasonography can provide valuable clues. Bronchoscopy was the most common method for making a diagnosis, as it can be used to find the abnormal opening of the fistula and the overflowing bile via the opening[13,14,16-19]. 3D-CT reconstruction can accurately detect the existence of the fistula, which is of great significance for diagnosing CBBF. In the present case, the CT scan provided us with the first evidence of the abnormal fistula. Then fiberoptic bronchoscopy was performed, and a contrast dye was injected into the fistula once the opening was confirmed. Next, a radiographic examination was conducted; thus, the opening, shape, and connection of the fistula were all confirmed. The result of our treatment was excellent, and to our knowledge, this method has not been reported previously.

Surgical resection was the ultimate treatment of choice, but a specific method must be considered according to different anatomical structures[20-22]. According to previous reports, different kinds of operative methods have been used, such as hepatic lobectomy, anastomosis of the gallbladder or intestine with abnormal fistulas, and fistula resection. We think that it is necessary to consider whether there is a biliary tract anomaly when preparing an operative plan. If a biliary anomaly exists, biliary reconstruction must be considered[4,14]. We performed laparoscopic cholangiography first during the operation to exclude biliary atresia, and achieved a satisfactory result. We performed thoracotomy subsequently, and explored and identified the fistula in the mediastinum; the fistula formed down the right side of the esophagus. We punctured the lumen for assurance because there are many important structures nearby, and then we injected methylene blue into the gallbladder; the dye was seen flowing out of the puncture site, thus the fistula was confirmed. Because the extrahepatic biliary tract was normal, reconstruction was unnecessarily considered. Instead, we just separated the fistula and ligated and sutured it at the upper end and at the hiatus, and then the fistula was removed.

The overall mortality of CBBF was 15.91% (7/44) according to the literature, and three patients died of respiratory complications without surgery. Our patient experienced chylothorax shortly after thoracotomy, which may be due to injury of the thoracic duct when we dissected the fistula at the hiatus. Fortunately, she recovered after short-term conservative management. Cholestasis was another main complication encountered postoperatively, and ultrasonography showed slight dilatation of the bile duct. We evaluated her conditions and prescribed methy-lprednisolone. Cholestasis resolved after three doses; therefore, we deduced that the jaundice may have been due to temporary inflammation of the biliary tract.

Most surgeons may not encounter CBBF in their professional career considering its rarity. Its clinical symptoms are typical and special such as bile-stained expectoration. As long as surgeons have some insight into this kind of condition, its diagnosis and treatment are not difficult, and the prognosis would be excellent for most patients.