Choledochocele: An unusual presentation in a premature neonate.

Choledochocele in a premature neonate who presented with obstructive jaundice and was managed surgically is reported. At 1-year follow-up, the child is asymptomatic.

INTRODUCTION

Choledochocele is a rare entity, particularly in premature neonates. Very few reports have been published in the English literature on this condition in infants. It is more common after the age of 5 years. A thorough search of literature did not reveal a single report in premature neonate.

CASE REPORT

A premature, 34-week-old, 930 g, male neonate was born by cesarean section to a hypothyroid mother. The first one month was complicated by hypoglycemia, seizures and low hemoglobin. The patient was on breast milk and also supplements. He had physiological jaundice on day 3 of life which required phototherapy. After phototherapy, his bilirubin was 4.6 mg% out of which direct component was 1.2 mg%. At the age of one and half months, the patient passed clay-colored stool and was icteric. It was negative for stercobilinogen. His obstructive jaundice work up showed raised bilirubin of 9.5 mg% with direct bilirubin of 6.5 mg% and raised alkaline phosphatase 1020 IU. The ultrasonography had normal biliary tract with no dilatation of biliary radicals. Common bile duct diameter was 4 mm. At this point, surgical opinion was sought by the pediatrician. Hepatobiliary imino-diacetic acid (HIDA) scan was not conclusive as there was uptake by liver as well as early excretion, but there was no progress of dye in the intestine during 24 hours. So, exploratory laparotomy was done keeping in mind about the biliary hypoplasia or inspissated bile syndrome.

The patient's weight was 1.2 kg when he was taken for surgery. Gallbladder was distended and there was bile on aspiration. The extrahepatic biliary apparatus was normal. Intraoperative cholangiogram suggested dye was going in the pancreatic duct, but there was no dye in the intestine with terminal dilatation of CBD [Figure 1]. After kocherization, longitudinal duodenotomy was done in the second part of duodenum. On duodenotomy, there was choledochocele of size of less than 1 cm in diameter [Figure 2]. A vertical incision was taken on the cyst. There was gush of bile [Figure 3]. Because of very small choledochocele, we were not able to excise the mucosal lining of the cyst nor were we able to suture incised edges and take biopsy of the wall. Also, we could not identify opening of pancreatic duct. On table cholangiogram confirmed the presence of dye in the intestine [Figure 4]. Later, duodenotomy was closed. The postoperative period was uneventful. His bilirubin after 2 weeks of surgery was normal and stool was normal looking. A follow-up HIDA scan after 6 months had good uptake and free flow of dye in the intestine. At 12 months follow-up, the child was asymptomatic and thriving.

Figure 1

Dye going into pancreatic duct

Figure 2

Longitudinal duodenotomy with choledochocele

Figure 3

Gush of bile after taking incision on choledochocele

Figure 4

Dye going into the duodenum

DISCUSSION

According to Todani et al[1-3] classification based on cholangiogram, a choledochocele was classified as type III. The common age in pediatric patients is around 5 years where the child presents with pain in abdomen. Manning and associates[4] reviewed 40 cases of choledochocele and described two main anatomic variants. In the most frequent form, common bile duct and pancreatic duct open separately in the intraduodenal choledochocele, whereas in the less frequent form, choledochocele is the diverticulum arising from the terminal end of common bile duct at the end of ampulla of Vater and pancreatic duct opens at its usual position. Mostly, it is diagnosed on ultrasonography where one can see a cystic mass inside the lumen of duodenum. In adults, upper gastrointestinal (GI) studies show radiolucency because of choledochocele.

Another important investigation is magnetic resonance cholangiopancreatography (MRCP). Chen et al.,[5] have proved its application even in infants where free breathing cholangiography was done at the end of expiration. In our case, due to technical and financial restraints, we were not able to do MRCP. But MRCP gives good anatomy and diagnosis.

Current established management of choledochocele is endoscopic retrograde cholangiopancreatography (ERCP). Even in pediatric age group, the management that has been advised is ERCP whenever facilities are available as it is diagnostic as well as therapeutic. Wilkinson et al.,[6] have done duodenoscopy in very small infant using 7.5 mm duodenoscope. As duodenoscope of this size was not available, we had no other choice than to go for open procedure. Suggested management[7] in open procedure is unroofing of the cyst beginning at the aperture and then reapproximation of mucosa with multiple interrupted absorbable sutures. Also, it is important to identify and calibrate the entry points of common bile duct and pancreatic duct to determine whether sphincteroplasty is necessary or not. But in our case this was practically not possible. Sphincteroplasty is necessary in many cases as the duct opening is narrow owing to chronic inflammation. If no internal drainage procedure can be done, then on rare occasion one may require pancreaticoduodenectomy.

Histopathologic feature of choledochocele is presence of biliary mucosa. But there is frequent observation of presence of duodenal mucosa on the inner lining of the choledochocele, which suggests a congenital duodenal anomaly.[8912-24] Also, for this reason, existence of congenital and acquired choledochocele has been hypothesized.[14] In our case, we were not able to take the biopsy.

As in any case of choledochal cyst, there is high chance of malignancy in non-operated case of choledochocele. Ohtsuka et al.,[9] from Japan in 2001, reviewed their data of 11 choledochoceles with prevalence of 27% of periampullary carcinoma, which was significantly higher than those without choledochocele. While Mehmet et al.,[9] are of the view that after ERCP with sphincterotomy, there is low malignancy risk because of regression of cyst, and they think follow-up is safe after sphincterotomy. On the other hand, it has been reported in some of the publications that resolution of the cyst can occur after sphincterotomy through ease of biliary and pancreatic drainage.[1011] The overall risk of malignancy is thought to be much lower in choledochocele, which is 2.5%.[1220]

CONCLUSION

Though rare, one should suspect choledochocele whenever dye is not progressing in the intestine in delayed images of HIDA in cases of obstructive jaundice. A simple incision on choledochocele relieves obstructive symptoms with the result confirmed immediately by doing intraoperative cholangiogram. However, long-term follow-up is necessary to know the efficacy of this procedure.